Instead of using 1 dictionary for all index paths we use N dictionaries with N being the number of sections.

We were looking if the numberOfStoryHeights > numberOfStoriesForCategoryInSection but all categories do not have the same number of stories.

Fixed #165 #166.
Removed cached heights that are not in tableview after reload.
initialize dictionary with nil
Set the correct frame and bounds before adding constraints.

Fixes #202.
Merge branch 'refs/heads/3.6/ipad-news' into 3.6/ipad-news-small-fixes
Merge branch 'refs/heads/3.6/ipad-news-estimatedHeightForRowAtIndexPath' into 3.6/ipad-news-small-fixes