Eliminate nearly all direct GitBlit singleton references in Wicket
This is the first step towards modularization and injection. All
direct references to the GitBlit singleton within the Wicket pages
and panels have been replaced to proxy methods in the GitBlitWebApp
singleton. There are still two Wicket classes which rely on the
GitBlit singleton; those require manual instantiation (servlet 3).
Change-Id: I0cdbbcf87959d590c446c99abb09c07c87c737bc
Renamed pushlog to reflog to better match it's current and future purpose.
Split PushesPanel into ReflogPanel and DigestsPanel.
Overhauled project pages and gave them a coherent purpose from the dashboard.