Change copyright header
Replace Makefile with Gruntfile

- Add package.json for devDependencies (mainly)
- Add bower.json for later publishing to bower
	- Generated from package.json using `grunt sync`
- Fix various jshint errors
Upgrade to Strophe.js v1.1.1

Upgrading to Strophe.js v1.1.1 brings us WebSockets and
several bugs have been fixed.
However, one thing has not yet been merged in, see src/core.js#L358.
We should test if this sync mode is still needed anyway. If yes, we
should fix this again in strophe.js and maybe create another pull
request.

TODO documentation:
  - Websockets
Upgrade to jQuery >= 1.9

Removes the two remaining $.browser checks.
ESC stopping all events has been fixed in
[Firefox](https://bugzilla.mozilla.org/show_bug.cgi?id=614304).

About the IE check I don't really know why we had it in the first place.
Do you remember @pstadler?
If we still need it, we might need to check it in another way.
Display error message if autojoin empty

Hopefully get rid of a lot of support emails
with this change.