v2.0 RC3

This is the third release candidate of the 2.0 series, aiming for a 2.0 stable release.
See the readme for release information, and changelog.txt file for detailed changes.

Changes in this release:
-Report on the number of joystick buttons on startup
-GUI: Have progress dialog show elapsed and estimated times
-Engine Manager: added uptime display
-VM: properly handle cancel functionality for additional engines
-VM: Only close progress dialog when loading engine count reaches 1
-VM: if an engine fails loading, switch to the next available engine even if it's in a loading state
-Allow building loads to be cancelled from the progress dialog
-Added the new 2.1 intro music as alternate music
-ScriptProc: adjusted the map zoom levels in the Triton Center and "Simple - Map" buildings
-ScriptProc: Added SetCameraZoom command
-Triton Center: added a map screen to the Lobby service area
-Triton Center: added the new intro music in the grand ballroom
-Disable models on Direct3D11 renderer, allowing buildings that contain models to load
-VMConsole: added engine runtime to ps function
-VMConsole: don't show the simulator time if no sky system is loaded