Removed a warning about comparision between signed and unsigned variable in ffmpeg_decoder.

Signed-off-by: Lukasz Gromanowski <lgromanowski@gmail.com>
Removed a warning about comparision between signed and unsigned variable in ffmpeg_decoder.

Added ifdefs because changes in API were introduced in libavc 56.1
and this code doesn't compile with older versions (ie. on Ubuntu, or Debian)

Signed-off-by: Lukasz Gromanowski <lgromanowski@gmail.com>
Simplified casting when comparing to AV_NOPTS_VALUE.

AV_NOPTS_VALUE is casted to int64_t when compared with pts,
so with libavc >= 56.1 it should be no-op because in that version
it's already signed int.

Signed-off-by: Lukasz Gromanowski <lgromanowski@gmail.com>
Experimental, compiles but does not work.
Fix duplicate calls to OEngine.  Use correct position, rotation and scale.  Debug draw not working.
Debug rendering toggled by double clicking the right mouse button.  Raycasting works, but inaccurate.
Added debug lines to show ray hit position.  Added highlighting the Entity hit by the ray.  Incorporated user setting far clip distance.
Fixed issue with mouse picking accuracy.
Minor refactoring and cleanup.
Make gcc happy.
Avoid Ogre exceptions and null pointers.
No physics or mouse picking for object preview.
Convert PhysicsSystem to a singleton.
Store object reference id to RigidBody instead of scene node handles.
Use QString rather than std::to_string
Merge remote-tracking branch 'upstream/master' into mouse-picking
Add settings to enable/disable debug rendering of mouse picking.
Add terrain collision.  Support visibility mask for objects and terrain.
Cleanup bullet objects in the destructors.
Use the correct name for deleting objects.