[Unified-mailman] minor SP6 correction

[Carl C Dietrich]

In deliverable 7 part 2 of SP6 when calculating the structural loads the
assumed layer thickness should be 0.2 inches of carbon fiber cloth
instead of the .12" listed in the handout (if you've already done the
calculation with the .12" you will not be docked, but your values may
look odd -- just make a note on your SP).  Also it is assumed that the
cloth is unidirectional (parallel to the span).

Sorry about the confusion.

-Carl