Enemy base function and following object, spawning mechanic

Base types added,
Script added for enemy to follow
Basic script added for enemy to spawn another(need to add more control
to it).
Cleanup and  added control to EnemySpawner
Merge branch 'master' of github.com:sagivo/Unity2d-Game
Merge pull request #6 from Ds886/master

Enemy base function and following object, spawning mechanic