Proposed tests for fix_import.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
Fix addition for __future__.absolute_imports by fix_import

The 2to3 fixer makes no changes if it guesses that all the imports are
absolute. We still want to add absolute_import in that case, however.
Make __future__ import check more robust
Update fix_imports_six tests for addition of absolute_import
Use our own touch_import in fix_int_long_tuple, so absolute_imports is added
Merge pull request #86 from python-modernize/85-test-fix-import

Tests for fix_import; also change the fixer to add 'from __future__ import absolute_import' even if the 2to3 fixer makes no changes.