Use absolute import

Only skip absolute imports when the only import is a __future__
statement.

Closes #59
Bump the priority of fix_import

Guarantees it does its thing before any other fixer accidentally blocks
its execution.
Merge pull request #77 from brettcannon/future_import

Use absolute import
Merge remote-tracking branch 'upstream/master' into fix_file_open
Drop the run order for fix_open

Because of the way the pattern has to be structured it is unnecessary.