diskline: accretion disk line emission, relativistic

A line emission from a relativistic accretion disk. See Fabian et al. (1989). Setting par2 to 10 is the special case of the accretion disk emissivity law $(1-\sqrt{6/R})/R^3$.

par1	line energy
par2	power law dependence of emissivity. If this parameter is 10 or greater then the accretion disk emissivity law $(1-\sqrt{6/R})/R^3$ is used. Otherwise the emissivity scales as R $^{\mbox{par2}}$
par3	inner radius (units of GM/c$^2$)
par4	outer radius (units of GM/c$^2$)
par5	inclination (degrees)
norm	photon/cm$^2$/s in the spectrum