Created Frame class

Created a Frame class, which holds an arbitrarily-sized two
dimensional array of RGB triples.

* frame.h - Created Frame class interface.

* frame.cpp - Created Frame class implementation.
Updated makefile

Added build instructions for the Frame class to the makefile.

* Makefile - Added instructions for frame.h and frame.cpp.
Created Frame test program

Created a program to test the features of the new Frame class.

* main.cpp - Created test code for the Frame class.
Merge branch 'frame' into develop