Move cache manifest to *.appcache

https://github.com/zhukov/webogram/issues/278#issuecomment-43072649
Improved grouping messages

Now displaying unread icon for grouped messages
Increase group timeout to 5 minutes:
https://github.com/zhukov/webogram/issues/177#issuecomment-42838841
Improved gulp task for cache manifest
Notifications: added possibility to modify volume.
Bugfixes
Improved send order
Added notifications volume setting

#285 Merged
Firefox fixes
Chrome fixes
Added audio filter
Added recent emojis tab

Closes #133
Closing emoji menu on message send

Closes #294
Welcome page improvements
Bump version tp 0.1.2