show only once unread messages at startup when we have twice the same contact in 2 accounts. Fixes #2921

* we now handle roster push and roster reception
* changed version number in src/common/defs.py

 * remove js from some headers
 * set coding:utf-8 to allow real names in headers

 * Remove some licencing problems
 * To do: same for images
 * See #4200

we have that in all files. To at least lesser the confusion a bit, add
vim tags for that.
Additionally, fix wrong #! in a few files.

when the defs.py file is changed.