Port to latest gedit API

[tobimensch]

Hi,

I tried to port your plugin to the latest gedit api:
https://github.com/tobimensch/gedit-pycheck

1. pep8 isn't working

2. there's lots of bugs in there

3. but it kind of works ...

I don't really understand your code, I didn't do more than neccessary to port it.

Maybe you can use it or improve.

Greetings...
Tobi