Log Message:
Update to 7.51

Upstream changes:
Drupal 7.51, 2016-10-05
-----------------------
- The Update module now also checks for updates to a disabled theme that is
  used as an admin theme.
- Exceptions thrown in dblog_watchdog() are now caught and ignored.
- Clarified the warning that appears when modules are missing or have moved.
- Log messages are now XSS filtered on display.
- Draggable tables now work on touch screen devices.
- Added a setting for allowing double underscores in CSS identifiers
  (https://www.drupal.org/node/2810369).
- If a user navigates away from a page while an Ajax request is running they
  will no longer get an error message saying "An Ajax HTTP request terminated
  abnormally".
- The system_region_list() API function now takes an optional third parameter
  which allows region name translations to be skipped when they are not needed
  (API addition: https://www.drupal.org/node/2810365).
- Numerous performance improvements.
- Numerous bug fixes.
- Numerous API documentation improvements.
- Additional automated test coverage.

Drupal 7.50, 2016-07-07
-----------------------
- Added a new "administer fields" permission for trusted users, which is
  required in addition to other permissions to use the field UI
  (https://www.drupal.org/node/2483307).
- Added clickjacking protection to Drupal core by setting the X-Frame-Options
  header to SAMEORIGIN by default (https://www.drupal.org/node/2735873).
- Added support for full UTF-8 (emojis, Asian symbols, mathematical symbols) on
  MySQL and other database drivers when the site and database are configured to
  allow it (https://www.drupal.org/node/2761183).
- Improved performance by avoiding a re-scan of directories when a file is
  missing; instead, trigger a PHP warning (minor API change:
  https://www.drupal.org/node/2581445).
- Made it possible to use any PHP callable in Ajax form callbacks, form API
  form-building functions, and form API wrapper callbacks (API addition:
  https://www.drupal.org/node/2761169).
- Fixed that following a password reset link while logged in leaves users unable
  to change their password (minor user interface change:
  https://www.drupal.org/node/2759023).
- Implemented various fixes for automated test failures on PHP 5.4+ and PHP 7.
  Drupal core automated tests now pass in these environments.
- Improved support for PHP 7 by fixing various problems.
- Fixed various bugs with PHP 5.5+ imagerotate(), including when incorrect
  color indices are passed in.
- Fixed a regression introduced in Drupal 7.43 that allowed files uploaded by
  anonymous users to be lost after form validation errors, and that also caused
  regressions with certain contributed modules.
- Fixed a regression introduced in Drupal 7.36 which caused the default value
  of hidden textarea fields to be ignored.
- Fixed robots.txt to allow search engines to access CSS, JavaScript and image
  files.
- Changed wording on the Update Manager settings page to clarify that the
  option to check for disabled module updates also applies to uninstalled
  modules (administrative-facing translatable string change).
- Changed the help text when editing menu links and configuring URL redirect
  actions so that it does not reference "Drupal" or the drupal.org website
  (administrative-facing translatable string change).
- Fixed the locale safety check that is used to ensure that translations are
  safe to allow for tokens in the href/src attributes of translated strings.
- Fixed that URL generation only works on port 80 when using domain based
  language negotation.
- Made method="get" forms work inside the administrative overlay. The \ 
fix adds
  a new hidden field to these forms when they appear inside the overlay (minor
  data structure change).
- Increased maxlength of menu link title input fields in the node form and
  menu link form from 128 to 255 characters.
- Removed meaningless post-check=0 and pre-check=0 cache control headers from
  Drupal HTTP responses.
- Added a .editorconfig file to auto-configure editors that support it.
- Added --directory option to run-tests.sh for easier test discovery of all
  tests within a project.
- Made run-tests.sh exit with a failure code when there are test fails or
  problems running the script.
- Fixed that cookies from previous tests are still present when a new test
  starts in DrupalWebTestCase.
- Improved performance of queries on the {authmap} database table.
- Fixed handling of missing files and functions inside the registry.
- Fixed Ajax handling for tableselect form elements that use checkboxes.
- Fixed a bug which caused ip_address() to return nothing when the client IP
  address and proxy IP address are the same.
- Added a new option to format_xml_elements() to allow for already encoded
  values.
- Changed the {history} table's node ID field to be an unsigned integer, to
  match the same field in the {node} table and to prevent errors with very
  large node IDs.
- Added an explicit page callback to the "admin/people/create" menu \ 
item in the
  User module (minor data structure change). Previously this automatically
  inherited the page callback from the parent "admin/people" menu \ 
item, which
  broke contributed modules that override the "admin/people" page.
- Numerous small bug fixes.
- Numerous API documentation improvements.
- Additional automated test coverage.