odf_sh_sharpening function fix and new test

In odf_sh_to_sharp function, the r2_term was not set properly using function arguments when deconvolution matrices were built. Hence, for already normalized model such as SHORE, the deconvolution was failing. The deconvolution was running as if the input was a q-ball model. 

Also, the test testing this was too permissive with a 75 degree crossing angle. I have pushed it down to 45 degrees.
Good catch!