Log Message:
Update to 0.57

Changelog:
=== 0.57 - Mon  8 Oct 2012 ===
* Ported zim background process to use the multiprocessing module
  - this fixes app-indicator issues under Ubuntu Unity
  - adds support for quicknote and other plugins on Windows
* Reworked application framework and "open with" dialog, now also
  allows to set applications per URL scheme
* New plugin for using GNU Lilypond to render music scores - Shoban Preeth
* New Zeitgeist plugin - Marcel Stimberg
* Added template method to iterate days of the week for a calendar page
* Added pythonic syntax to access dicts to template modules
* Added tasklist option to take into account a Mon-Fri work week
* Fixed start of week and week number first week of the year for calendar plugin
* Added "untagged" category to task list
* Fixed strike out TODO label showing up in task list
* Added template editor dialog
* Added support for "forward" and "back" mouse buttons
* Added support for exporting to ReST - Yao-Po Wang
* Added new option to create and insert new attachments based on file template
* Added an argument to the quicknote plugin to import attachments
* Added icons per mimetype to the attachmentbrowser
* Added statusbar button for attachment browser
* Added monitors to watch attachment folder for updates
* Fix drag&drop on non-existing folder in attachment browser
* Fix drag&drop for attachment folder on windows
* Made location of plugin widgets in side panes configurable
  and reworked key bindings for accessing side panes and toggling them
* Made tags plugin to revert to standard index if no tag is selected
* Page completion now matches anywhere in the basename -- patch by Mat
* Patch to use sourceview in imagegenerator dialog - Kevin Chabowski
* Fix for insert symbol dialog to insert without typing a space
* Made image data pasted as bmp convert to png to make it more compact
* Critical bug fix for version control plugin
* Critical bug fix for xml.etree.TreeBuilder API for python 2.7.3
* Bug fix for exceptions in index - Fabian Moser
* Bug fix for interwiki links
* On windows fix for bug when home folder or user name contain non-ascii characters
* Fixed help manual opens in compiled windows version
* Fixed locale support on windows
* Added translations for Brazilian Portuguese and Romanian