Make indentation consistent in files with mixed indentation

[piotr1212]

I'm having trouble with my OCD by just looking at the files which mix indentation. Some files have a mix of two, four or even three spaces.

This patch sets the indentation to two spaces on all files with mixed indentation. This is just aesthetic It should not change any logic. I didn't touch the files which have a consistent four space indentation.

I would rather update everything to 4 spaces to comply with pep8 and add flake8 test, but don't know if that will get merged as that would change almost every line of code.

[coveralls]

Coverage remained the same at 88.291% when pulling 99a4030 on piotr1212:indentation into 4f2d2ac on graphite-project:master.

[coveralls]

Coverage remained the same at 88.291% when pulling 99a4030 on piotr1212:indentation into 4f2d2ac on graphite-project:master.

[coveralls]

Coverage remained the same at 88.291% when pulling 99a4030 on piotr1212:indentation into 4f2d2ac on graphite-project:master.

[deniszh]

I'm fine with that. Not sure if we need to migrate to 4 spaces, though.