Changed @reqs to @preqs

Renamed:
1	CodingColors.html : @reqs -> @preqs

Reasons:
1	This is now where you put anything that is assumed for this function,
	as well as anything that this function requires.  Assumptions must go
	here as well.

Modified:
1	CodingColors.html

Reasons:
1	Added question for tab vs space usage.