i18n: remove *.pot files from repo (they are autogenerated)

Doing a `make clean` was removing these files, and making 'git status'
dirty.
[Engine-Twitter] message hook support
Merge pull request #130 from knocte/master
[L10N] Removed MSNP/OSCAR left overs from po-*/POTFILES.skip
[Build] Added po-Engine-Twitter to POSUB
[L10N] Added po-Engine-XMPP text domain
Ignore auto generated pot files
[L10N] Added po-Engine-JabbR text domain
Merge branch 'stable'
[Engine-Twitter] Implemented useful TwitterMessageBuilder.Append() overloads
[Engine-Twitter] Refactored to use new TwitterMessageBuilder.Append() overloads
Remove empty files
Fix ChatViewInfoAttribute's namespace
[Frontend-GNOME-Twitter] Add support for unfollowing people

A new project Frontend-GNOME-Twitter had to be created.
[L10N] Add infrastructure for Frontend-GNOME-Twitter project