adding function for thermal distortion from bulk absorption and making functions conform with vinet09 structure

adding function which uses the FT_LG_clipping_loss analytic function for clipping of an LG mode to find the radius of a circular aperture which causes a given amount of clipping

can now take files with no maxtem/maxtem off and turn off prm and srm for all mirror/bs definitions (m,m1,m2 etc.)