0.2.0 Week 2 Update - Achievements, Tower Targeting, and Wave Spawning

Rewrote unit distance calculations to provide more accurate tower targeting
Fixed issue with waves spawning not being cancelled on game end, resulting in a massive amount of enemies spawning on the ship and not moving.
Fixed issue with achievements not triggering
Fixed issue with buttons not being clickable after completing season

Added Additional Achievements inline with unlocks

Moved hero to start of path