This allows jingle availability to be updated if contact sign in/out.
This patch will also wait for user acceptance before connecting.
This will, among other things, ensure that audio/video state won't be set to
JINGLE_STATE_CONNECTING while the connection is already up.

request bookmarks via XML if server announce it supports pubsub but doesn't answer in the next 30 seconds. Fixes #5198

A content has now to be accepted (user-side) before {content,session}-accept

If the number of connected resources is appended in parentheses,
the appropriate ltr or rtl mark is inserted before, so that the
writing direction at the end of the nickname matches the writing
direction of the whole displayed string as determined by
http://www.unicode.org/reports/tr9/#The_Paragraph_Level

new GUI to start audio and video sessions. TODO: ability to add/remove audio/video content to an existing session

don't remove a file before renaming under windows because os.remove('test') will remove 'TEST' under window. Fixes #5279