Log Message:
Update to 0.51

=== 0.51 - Tue 19 Apr 2011 ===
* Fixed critical bug with resizing images - Stefan Muthers
* Fixed bug preventing resizing of text entries in dialogs
* Fixed bug disabling auto-completion for page names in dialogs
* Fix so cancelling the preferences dialog will also reset plugins
  - Lisa Vitolo
* Fix to switch sensitivity of items in the Edit menu on cursor position
  - Konstantin Baierer
* Fix to handle case where document_root is inside notebook folder
  - Ji Janouek
* Fixed support for interwiki links in export
* Fixed "Link Map" plugin to actually support clicking on page names \ 
in the map
* Fixed copy pasting to use plain text by default for external applications
  added preference to revert to old behavior
* Disable <Alt><Space> keybinding due to conflicts with \ 
internationalization
  added hidden preference to get it back if desired
* Added support for organizing pages by tags - Fabian Moser
* Added feature to zoom font size of the page view on <Ctrl>+ / <Ctrl>-
  - Konstantin Baierer
* Added support for system Trash (using gio if available)
* Added Calendar widget to the "Insert Date" dialog
* Added plugin to sort selected lines - NorfCran
* Added plugin for GNUplot plots - Alessandro Magni