Added list of three most recently viewed mocks to the homepage. 

Noticed that mock views were being tracked, but not used for anything.
Because most users will likely be going to Mockr to look at the same
mocks over and over, a list of recently viewed mocks makes it easier
to find what the user is looking for.

To avoid confusion between "Recently Viewed" and "Recent Mocks" (the list
of latest mocks created), "Recent Mocks" was renamed to "New Mocks".