Make code more pythonic (1)

- sort imports alphabetically
-- first from LA import BLA, later import BLI
- use string formatters (i.e. 'Hello {0}'.format('World')
- try to use always single quotes (just for consistency)
- keep lines at 80 characters and wrap them if longer
- add a utf-8 header
- use python calls whererever possible (os.remove instead of
  os.system('rm something')
Add the utf-8 header to all python files
Make code more pythonic (2)

- sort imports (first from lorem import ipsum, later import LOREM)
- move data out of methods to keep methods more compact and easier
  to read
- use the new string formatting notation everywhere
- use single quotes whenever possible (mostly to keep consistency)
- keep lines at 80 characters long (not just for easy reading but also
  for easy comparing)
- no need for parentheses on conditions: i.e.
  if small < bigger: instead of if (small < bigger)
- no need to finish lines with semicolon
- use python calls whenever possible (i.e. shutil or os.remove)