libgd: Added libgd to cut-n-paste

A separate commit where libgd is added to cut-n-paste. libgd is used for the bookshelf
view of recent documents.
evince: Added bookshelf view for recent documents.
Some Style problems fixed
evince: Updated implementation of bookshelf view

Updated as per Jose's comments on the bug report.
few more improvements
Implemented saving of thumbnails in temp directory and metadata is also stored.

Partly implemented switching between document and bookshelf using a button.
The bookshelf button works properly now. Need to mark the currently open document.
Some minor improvements.
Using gtk_recent_info_get_modified now, instead of gtk_recent_info_get_visited for ordering the recent items.
Used gtk_recent_info_get_exists to ensure that the items added to
the bookshelf exist.
Changed the bookshelf button to a toggle button, which seems more
natural as we 'toggle' between the bookshelf the currently open
document.
Also fixed an issue reported by gpoo, regarding the button being
sensitive even when Evince is loaded without a document.
bookshelf: Changed blank translatable srings to regular blank strings

This was done in response to KaL's observation that using _(""), ie,
blank translatable string is not correct and causes problems.
bookshelf: Fixed the critical warning reported by gpoo

It was fixed thanks to KaL who noticed that it was happening because
I was trying to use the scrolled window before it had been constructed.
EvRecentView: Changed name from EvBookshelf to EvRecentView

Renamed EvBookshelf to EvRecentView based on KaL's comments. It
sounds more appropriate.
EvRecentView: Adding the files for EvRecentView

Forgot to add the EvRecentView files in the last commit. Adding them now.
EvRecentView: Fixed Makefile.am to build ev-recent-view instead of ev-bookshelf

Updated the Makefile.am so that it is in accordance with the name change from
EvBookshelf to EvRecentView
toolbar: Changed Bookshelf/RecentView button back to a normal one

Previously, this button had been changed to a toggle button. Now,
since a different toolbar will be displayed with the bookshelf/recent
view, it makes more sense for this to be a normal button.
EvRecentView: Implemented a different toolbar for bookshelf/recent view

Added a new EvMinimalToolbar which is displayed while in bookshelf/recent view,
instead of the full regular toolbar.
ev-application: Fixed a tiny warning occuring because of a missing type conversion

The called function was expecting an EvWindow * whereas I was passing a GtkWidget *.
Fixed it by using the appropriate type conversion.
EvRecentView: Removed unused get_property and set_property