Reorganized the project structure.
Added in a test level 3 for now, but got the gravity systems and upside down jumping working.

How it works:
1.  Place trigger at beginning of level to change global gravity
2.  Place Player gravity triggers to flip the gravity for the player
exclusively.  This can be done as many times as needed.
3.  Some code was duplicated for the inversion cases in
Player_Movement_Script.
Cleaned up the gravity changing code a little more.  Using Update to Fake player gravity did not work properly.
Modified jump values for the player in the L3 test level so that the player could not fly all over the place.
Modified player jump values further in L3.
Added sky background to L1
Added in Spinning Background for L3.
Added in camera lerping to a negative y offset when the player flips to the reverse gravity.  Without this, there would be camera clipping.
Merge branch 'master' into L2DEV

Conflicts:
	Library/assetDatabase3
	Library/expandedItems