Created homescreen

Summary of Commits:
-Created a home screen that is close to the design doc's home screen, but I added another button that will give you the option to go to your list of conversations. 
-Made shyHi logo the new launcher, and edited manifest so that the home screen appears first
-Create a progress screen
-Created a custom row model, custom row adapter, and custom row xml for the conversations page. All set up, just needs to be connected to the json data.