Crate greeks

Functions

delta_call	Calculates the delta of a call option.
delta_put	Calculates the delta of a put options
gamma	Calculates the Gamma for an option
gamma_d1
rho_call	Calculates the Rho of a call option
rho_put	Calculates the Rho of a put option
theta_call	Calculates the Theta of a call option
theta_put	Calculates the Theta of a put option
vega	Calculates the Vega of a given option
vega_d1