libview: Cycle through form fields with tab button

https://bugzilla.gnome.org/show_bug.cgi?id=503706
help: Remove EvOpenRecentAction symbols from the docs
Fix some make distcheck issues
backends: Do not generate appdata files from makefiles

Substitute the mime types from configure instead to avoid adding
generated files to POTFILE.in that is problematic.
Fixing annotation window colors

The annotation window now is all of one color and
no border.
Improving annotation window appearance

The title is now bold and there is extra margin
space around the textbox.
Also fixing minor typo.
Closing annotation window by clicking on icon

When the annotation window is opened, clicking on
the corresponding icon closes it.