Command - Changed execute() to return a Result object.
CommandController & AddCommand - Set up general flow of method calls.
Revert "Command - Changed execute() to return a Result object. CommandController & AddCommand - Set up general flow of method calls."

This reverts commit 7c3d9e1e2d8d91305257f3253111831e3e29aa30.
Merge branch 'master' of https://github.com:443/cs2103aug2014-w11-1j/main.git
Added flow of add command class; TODO: parsing.