Added OSC images and grid layout
Strings and code for GridView
More changes to add GridView to landing screen
Changes to improve style of landing screen and nav drawer.
images and code for CNX book titles
images for CNX book titles
images for CNX book titles
Fixed title text
Added correct URLs for CNX books and fixed a title typo
Removed OSC books without content and fixed title typos
Changed Books to Textbooks
Merge pull request #11 from Connexions/add-grid

Add grid of Book covers to opening screen