tower update w/ a touch of refactoring as always

tower successfully detects agent when in range and toggles the shoot
method. Currently the shoot method only toggles wonder laser text in the
terminal. Actual shooting coming soon!
Also! you can now place towers with the EQUALS button on your keyboard
when you have a node selected.  HOWEVER, it is placed in the plane, and
i'm not sure how to fix it yet.
Also, updated tower to shoot with regard to deltaTime