SOL-20 add content type filters instead of extension, fix css issues, add filter text to pagination header
SOL-20 Fixing tests to include filter column
SOL-20 PEP8 fixes
Merge pull request #338 from edx-solutions/dcikatic/SOL-20-filter-changes

Dcikatic/sol 20 filter changes - merging to get eyes on - still need to confirm correct test coverage