fixed encoding issues, now can post special caracters again.

Issue were also "not so special" characters like ! () and so on (i.e. smilies). jQuery uses encodeURIComponent for that. But that does not encode most of these punctuation characters and it seems that is necessary for the newer twitter api (see here: https://t.co/YhQITjRKeK)

Encoding is specified for them, too: http://www.w3schools.com/tags/ref_urlencode.asp

Macaw uses jsOAuth library which has an urlencode method that can do exactly this, i.e. it encodes all necessary characters. The library is released under the MIT License, so I just copied that URL into a new file and use it now from Spaz also.