Fix formatting errors in datagrids module according to PEP8

Fixed the following format errors:
datagrids/columns.py:460:27: E251 unexpected spaces around keyword / parameter equals
datagrids/columns.py:460:29: E251 unexpected spaces around keyword / parameter equals
datagrids/grids.py:166:5: E303 too many blank lines (2)
datagrids/grids.py:167:80: E501 line too long (94 > 79 characters)
datagrids/views.py:177:50: W292 no newline at end of file

Testing Done:
Ran unit tests for datagrids module, and ran pep8 again.

Reviewed at https://reviews.reviewboard.org/r/6629/