adding co-f distribution
surviving a SSD crash.

things are in an inconsistent state, halfway through del_sropt change.
bleah.
Merge branch 'spantest' of https://github.com/shabbychef/SharpeR into spantest

Conflicts:
	R/sr.r

ack. ack!
futzing with del_sropt
plowing towards del_sropt ...
adding sr_vcov to the exported functions.
adding to documentation.
moving towards finally the F test.
still working on del_sropt.

something wrong with the calculation. I do not understand R properly...
fixing spantests
working towards spantest; docs and such
vignette was running at high-res.
fixing Giri result, and adding to sr_vcov doc
futzing with spantest
finishing off del_sropt and spanning?
Merge branch 'master' of github.com:shabbychef/SharpeR