[suggestion] add instruction on adding path to Radiance in Mac OS X

[hopezh]

I'd suggest adding instruction like the following regarding Radiance as part of ladybug installation guide for Mac OSX.

"... the NREL mac and linux packages do not automatically set the PATH and RAYPATH env vars for you. Here is what I have in my ~/.bash_profile:" (or, ~/.zprofile for z shell (zsh))

## Radiance path crap
export PATH=$PATH:.:/usr/local/radiance/bin
export RAYPATH=.:/usr/local/radiance/lib
export MANPATH=$MANPATH:/usr/local/radiance/man

Source: NREL/Radiance#24 (comment)

[chriswmackey]

Hi @hopezh ,

The NREL distribution of Radiance is essentially unusable by LBT Grasshopper. This is not just because of the incorrect default installation folder but also because the NREL version of Radiance is too old and lacks several features used by the plugin. The compatibility matrix always has the correct links:
https://github.com/ladybug-tools/lbt-grasshopper/wiki/1.4-Compatibility-Matrix

Should we just link to that in the installer.gh?