Make sound design more consistent, beautify pickup orbs, and fix a bug

All SFX are now 8bit courtesy of LSDJ, pickup orbs look like PURE ENERGY, and fixed a bug which prevented selection of a tower behind another tower.
Add ability to build different towers
Add ability to build regular buildings
Buildings can now increase your internet presence rate
Fixed bug where points were added if time ran out. Added enemy damage
Fix Main UI text boxes
Fix bug where gimmick would disable next wave
Add prefab for first level introduction
Add all level intro emails
Merge with Aaron's branch
Change UI sounds again