BUILD: Enable RTTI again.
DEVTOOLS: Enable RTTI in create_project generated project files.
SDL: Let SdlGraphicsManager inherit from GraphicsManager.
SDL: Make activateManager/deactivateManager SdlGraphicsManager specific.

We can do this now that we can use virtual inheritance and dynamic_cast
because we enabled RTTI.
SDL: Further small cleanup related to manager switching.
AGOS: Slightly clean up ArchiveMan code.

This removes the (always true) _fallBack flag which determined whether
SearchMan should be searched.
AGOS: Get rid of ArchiveMan in favor of global SearchMan.

This in fact slightly changes the priority order of added archives. Formerly,
all archives in SearchMan were preferred to the customly added ones in
ArchiveMan. All standard paths (i.e. path and extrapath) will be still be
searched before the custom ones (which are all priority 0 right now) but system
specific paths will be searched after (due to their priority being -1). Since
system specific paths shouldn't contain any game data files this should
hopefully be harmless.

This wasn't tested for games with CAB archives.
AGOS: Use Common::File instead of SearchMan.

This makes sure the hack from Common::File for filenames with a trailing dot
is used as expected.
ENGINES: Introduce method Engine::initializePath which sets up SearchMan.

This replaces the hardcoded addition of the game path in runGame in
base/main.cpp by an engine configurable one.
TINSEL: Take advante of Engine::initializePath.

This makes sure that the game path is only ever added once for the PSX version
of DW1. Most noticably this will make the warning about the game path being
present in SearchSet disappear on startup.
AMIGAOS4: Make isReadable return false for non-existent files

This also properly initializes _bIsValid for non-existent files.
For consistency, isWritable() is changed analogously to isReadable(),
even though it should not lead to changes in behaviour.
AMIGAOS4: Allow getParent() to work for non-directories
AMIGAOS4: Clarify virtual fs root node
Merge pull request #424 from wjp/amigaos4-fs

AMIGAOS4: FSNode fixes
FULLPIPE: Initial code for sceneFinal
FULLPIPE: Plug sceneFinal in
FULLPIPE: Implement sceneFinal_updateCursor()
FULLPIPE: Implement sceneHandlerFinal()
FULLPIPE: More code to sceneFinal
FULLPIPE: Implement sceneHandlerFinal_fallCoin()