libCGAL not found on OSX

I'm attempting to install MemSurfer via the online instructions, and wound up with a problem when I attempt to actually run the installation script. I installed CGAL via homebrew, however, this is a header-only library, and so when I try to setup MemSurfer I get the following error:
```
> MemSurfer = (/Users/cedelmaier/Projects/Biophysics/MemSurfer)
> CGAL_ROOT = (/usr/local/Cellar/cgal/5.4/)
> EIGEN_ROOT = (/usr/local/Cellar/eigen/3.4.0_1/)
> BOOST_ROOT = (/usr/local/Cellar/boost/1.78.0_1/)
Traceback (most recent call last):
File "/Users/cedelmaier/Projects/Biophysics/MemSurfer/setup.py", line 160, in
PATHS = fetch_paths(os.path.join(PATH_MEM, 'external'))
File "/Users/cedelmaier/Projects/Biophysics/MemSurfer/setup.py", line 106, in fetch_paths
paths['cgal'].update({'lib': find_shlib_path(paths['cgal']['root'], 'libCGAL')})
File "/Users/cedelmaier/Projects/Biophysics/MemSurfer/setup.py", line 63, in find_shlib_path
raise Exception(f'Find_shlib_path({path},{libname}) failed!')
Exception: Find_shlib_path(/usr/local/Cellar/cgal/5.4/,libCGAL) failed!
```

So really, need to know if the library is really needed, or change the installation instructions for the brew installation version to accommodate the different installation types.

Start with setup.py, especially fetch_paths and find_shlib_path around the reported lines, and review the online installation instructions for Homebrew CGAL. Determine whether the libCGAL lookup matches the Homebrew package, then update the setup behavior or instructions so installation works with the stated dependency layout.

Written by the indexing model from the issue text.