kdblur2: convolve with the laor2 model shape

A convolution model to smooth a spectrum by relativistic effects from an accretion disk around a rotating black hole. The accretion disk has a broken-power law emissivity profile. Uses Ari Laor's calculation including GR effects (Laor 1991https://ui.adsabs.harvard.edu/abs/1991ApJ...376...90L/abstract). Modified from laor2 model by Andy Fabian and Roderick Johnstone.

par1	Index: power law dependence of emissivity (scales as $R^{-par1}$)
par2	inner radius (units of $GM/c^2$)
par3	outer radius (units of $GM/c^2$)
par4	inclination (degrees)
par5	radius at which emissivity power-law index changes
par6	Emissivity power-law index for radii >par6