Update the structure of the classes to include protected variables for non-point classes
-Adds to program security and helps to create a more reliable infastructure for later on

Decided to add thickness variable
-Allows non xy-planar objects to collide; will add to the realism of the game

Added some constants
-Allows easy control of program 'settings'

Signed-off-by: Giovanni Finney-Long <giorulesall@gmail.com>