Students T-Test

Added functions for Students T-Test one sample and independant sets and a function to convert a t-value to a p-value. Not sure about the naming, if you would like me to change the function names and resubmit requrest, let me know. I have tests, I will add examples next week and I would like to add dependant sets after that.
Your point that people are looking for StudentT is well taken

test.TTest is a bad name. test.T is also a bad name, because the one character makes it feel like it's more fundamental to the package than it actually is.

Can we instead call it "StudentT" and add a flag to perform either operation?
StudentT( ..., equalStdev bool)

Just trying to think out loud about the best way to fix