add bonus property that gives exp whenever staff user heal
modify to spawn heal button when atleast one of the player is below max_health
modify the heal code only when friendly user is less than max health
modify heal code
include exp function for staff1
modified so that heal button will spawn only if atleast one unit is injured
modified heal code
uncommented health_max, and cleared out comments
modify check to not use heal if player has max health
Merge pull request #43 from mk200789/master

modified experience system
Minor code formatting fixes.
Adding prototype of shop system
Merging
Fixing merge conflicts