Make sure presence stanza is sent out after roster update

specifically also when localstorage is populated
Bugfix. Don't reconnect while strophe is still disconnecting

Causes infinit loop of connects and disconnects
Add Dutch translation, provided by @maartenkling
Fix tests. sendPresence is now sent out at a different place
New release, 0.6.6
Add bitcoin address for donations
Also add address to index.html
Use @thomascube's roundcube add-on fork.
IE8 bugfix. Fixes #52
Don't unnecessarily create objects for roster items
Bugfix. Wrong global variable set
Fix RST formatting in readme

Conflicts:
	README.rst
Bugfix. Roster didn't appear in some cases.

Make sure the last roster item is still added (even if it's a zombie), so that
the roster will be shown (roster is only shown when last_item property is
true).