Added basic support for SteamUtils in Bridge.
Updated Bridge Makefile.
Removed some extra includes.
Renamed SteamAPIContext to just Context.
Renamed core to state, as part of code cleanup.

1. Also updated the Makefile.
2. Note that this breaks Bridge compilation.
Cleaned up Bridge state class/files.
Reimplemented the Core Bridge API calls.

1. Has it's own file now, core.cpp.
Updated the Bridge Makefile.
Updated Bridge's callback code.

1. Uses the new State class.
2. Lots of logging fixes.
3. Misc polishing.
Updated Bridge apps code to use State.

1. Plus various polishing and logging fixes.
Updated Bridge client code to use State.

1. Plus misc polishing and logging fixes.
Updated Bridge Friends and User code to use State.

1. And misc polishing and logging fixes.
Updated Bridge Utils & UserStats to use State.

1. Plus misc polishing and logging fixes.