destroy(lib): all exercises will now be in coffee

I discovered that if I specify the file extension on the path
of node's export mechanism, then it will interpret the file as that
respective file type. (thereby overriding the .js default file extension)

retroactive changes have been made to the previous exercise, as well
adjusting the Cakefile task for creating new exercises
feature(exercise): FirstFactorial from Coderbyte
Merge branch 'exercise-first-factorial'

Conflicts:
	bm/firstReverse_bm.js
destroy: extraneous js files that were unconverted