Revised class comments.
Fixed a bug in updateClockDisplay that was causing the system clock to be partially obscured.
Added a wrapper div to allow the content to be centered.
Added a div for the memory display table.
Added code to initialize the reference to the memory display device.
Added code to instantiate and initialize main memory.
Added functions to model the 6502 instruction set.
Modified the cycle function to include the fetch, decode, execute cycle.
Created a utility method 'fetchOperand' for reading a two-byte  operand from main memory.
Implemented the MMU which provides methods for reading/writing to main memory and allocating/deallocating memory blocks.