Improve hash generation performance.

The idea is to snap the position to an integer grid.
Move arithmetic out of loop.

This should do exactly the same in all situations.
Add PM_WORST_QUALITY macro.

Also remove singular triangle destruction,
because it holds up 3 vertices just for a single triangle.
Use multiplier for seam cost strengthening.

This will scale better with edge length.
However if the seam is on the middle of a flat surface, it would create a hole early.
To protect from that, we use the 0.001/2 cost shifting.
Inherit seam property.
Cleanup baking.

Fixed issue, where buffer is not unlocked.
Also use memset for zeroing, because its cleaner.
Use Ogre::LogManager for warnings.
Add PMInjectorListener support.

Also clean up the mess with FrameListener.