Convert indentation from tabs to four spaces

Let's be nice Pythonistas
Rearrange imports to relative imports, fix bug

- Fixes bug in queries.py which did not import
  builtin exceptions that is used
- Relative imports break tests.py as script, execute 
  as module: python -m zeit.api.tests
Make code conform to PEP8

Sorry for being a PEP8 nazi
Merge pull request #20 from stefanw/indentation-pep8

Indentation to 4 spaces / PEP8 / import missing fix