Update project for Direct3D draw manager so it looks in DXSDK_DIR

This is set by the directx sdk installer.
Update documentation references.

This resolves issue #41.
(cherry picked from commit 9ba5907dccd70aa5b51a06e6b8a0b242082b2cdf)
Merge branch 'add-dxsdk-dir-3.0' into 3.0-improvements
Fix a crash if no user is currently available in OSG

(Trying to de-configure and re-configure at runtime)
Merge branch 'fix-user-crash' into 3.0-improvements