Add tower range visualization

Also move rename texture folder I made to sprites cause that makes way more sense
Merge branch 'christian_staging'
Embetter tower range shader by stealing one from the internet
Extensive UI update
Merge branch 'ron_staging'

Conflicts:
	Assets/Scenes/DebugLevel.unity
Pivot the camera upward in build mode for visibility
Camera panning, UI prefabbed, music changes
Scale panning speed based on distance from camera.
Improve visibility of healthbars
Various UI improvements
Add tower selection behavior

Still need to make it look pretty, but it works. Also, beware that raycasts now ignore triggers. If that is a problem let me know.
Slightly adjust camera pivot point position
Merge branch 'christian_staging'
Restore misc UI functionality
Make tower select look a little better

Range grows outward on select and shrinks inward on deselect
Merge branch 'master' into christian_staging
Tower menu now rotates to face camera

also moved tower scripts to their own folder because wow
Greatly improve tower selection visuals

Added creative commons menu icons, hover animations, and tweaked some other smaller details
Add upgrade tower prefab
Add tower deletion and upgrade functionality

could still be made more robust