Replace capital first letter for param and return names

[dagood]

          nit: why CAPS for the `X` `Y` param names?

Originally posted by @derekparker in #135 (comment)

There are a decent number of existing names that can be cleaned up too--a few examples:

type BigInt
func GenerateKeyECDSA(curve string) (X, Y, D BigInt, err error)
func GenerateKeyRSA(bits int) (N, E, D, P, Q, Dp, Dq, Qinv BigInt, err error)

type PrivateKeyECDSA
func NewPrivateKeyECDSA(curve string, X, Y, D BigInt) (*PrivateKeyECDSA, error)

type PrivateKeyRSA
func NewPrivateKeyRSA(N, E, D, P, Q, Dp, Dq, Qinv BigInt) (*PrivateKeyRSA, error)

I've chalked this up to "spelling it how cryptographers do" in the past, so I'm indifferent, but we should probably decide.

[mertakman]

#172 solved this, please close this issue