Reworked alien spawning mechanics + Bug Fix IV

-Alien spawning is now independent of FPS.
-Aliens will now spawn at a set distance interval
-Able to set and get the spawning distance from Alien.cs. Default is 100
units

Bug Fixes:
-Removed the dog and pony show feature
-Selector generic removed, redundant
-Game Speed removed, redundant to Level Editor
-Defaulted min game speed to 0.25f
-Removed perceputal OR on GamePause due to console errors, use Events!
-Scale variable reassigned to PreferencesManager's alien speed