Incorrect AOI from pvl_singleaxis

[DanRiley]

pvl_singleaxis produces an incorrect AOI when the sun is above the earth horizon but behind the module plane.

Issue seems to be in this line of code.

Similar to issue 1221 for the python pvlib

[DanRiley]

I would recommend removing lines 202 and 203, and using pvl_getaoi near the end of pvl_singleaxis to calculate the AOI without constraint. That is, AOI would have the same constraints as those placed by pvl_getaoi.