VIDEO: Add support for seeking in AVI videos with an index

Rewinding will work in any AVI video
TSAGE: Some renaming in Scene250
TSAGE: R2R - Fix elevator behavior (scene 250)
TSAGE: R2R - More renaming in scene 250
TSAGE: R2R - Remove useless variable in scene 250
TSAGE: R2R - Get rid of some magic values related to eventType
TSAGE: BF - Fix erroneous check of eventType
TSAGE: R2R - Remove leftover warning
TSAGE: BF - Get rid of some magic values related to btnState
TSAGE: Core - Get rid of some magic values related to btnState
TSAGE: Fix for initialising inventory for new R2R games
TSAGE: R2R - Some renaming in scene 1000
TSAGE: Bugfixes for component slots in intact ship
TSAGE: Minor fixes for ship console display and scene 1700 setup
TSAGE: Necessary synchronisation fixes to R2R SceneExt and SceneArea classes
TSAGE: R2R - Some renaming in Scene 1100
MORTEVIELLE: Fix computation of elapsed time around midnight

Replace use of getTimeAndDate() by getMillis() when computing
elapsed time. This fixes an issue when playing around midnight.
Also rename some variables for clarity (since they contain a time
in seconds having Hour in the name was a bit confusing).
MORTEVIELLE: Freeze clock in game when pausing the game
MORTEVIELLE: Implement Engine::getDebugger()
TSAGE: Cleanup and fixes for R2R ring edge