IPF-58: IN-PROGRESS

- refactored research view controller to show top 20 posts
- removed flow of categories > tags > posts > post details
- fixed various XIB layout issues on iPad
- added excerpt to each post
IPF-58: IN-PROGRESS
IPF-58: IN-PROGRESS

- switched to collection view
IPF-58: IN-PROGRESS
IPF-58: IN-PROGRESS

- updated categories and tags view controllers to use collection views rather than table views
IPF-58: IN-PROGRESS

- all table views (except for documents) has been switched out to use collection views
- tested on both iPhone and iPad simulators
IPF-58: IN-PROGRESS

- search view now uses a collection view
IPF-58: COMPLETED

- everything is now a grid ...
Merge branch 'feature/IPF-58' into develop