Fixes issues introduced by https://github.com/swig/swig/pull/2238. As
obs-scripting is not compatible with the SWIGPYTHON_BUILTIN, obspython
needs to disable this feature.
The obspython.i file requires `ENABLE_UI` to be defined for the swig
compiler to pull in the actual obs-frontend-api header. If this is not
the case, swig will not discover the required methods and ENUMs and
in turn will not make those available in the scripting environment.
_obspython.so currently links directly against python as @rpath/Python
and has 3 common python install paths set as rpaths so it would only
work if a user had python installed at one of those hardcoded paths.
Don't link _obspython against python at all but instead link it with
"-undefined dynamic_lookup" so when it is imported by python all it's
undefined python symbols get resolved at runtime against the user
supplied python instance loaded into the process earlier.
The rpaths aren't needed anymore this way.
Uses the 'install' command in cmake to install scripting modules/files
(such as _obspython.so, obslua.so, and obspython.py), and changes the
install location of those files on all operating systems. If using a
non-unix structure install, those files will be installed in
data/obs-scripting/[32bit/64bit], otherwise with unix structure installs
those files will be installed to [/usr/local/lib]/obs-scripting.
