Allows the ability to install extra data from a specific absolute path
rather than a path relative to the cmake current source dir.  Useful if
say I want to generate data files in to the cmake binary folder rather
than put them in the data folder of the cmake source dir.

The actual plugin files get copied to obs-scripting/ without the
64bit subdir like everything else on MacOs, fix this path accordingly
otherwise the scripting home dir passed to Python is incorrect

Fixes the install_obs_data_file cmake helper function to be more
consistent across operating systems.

Allows copying an individual file (which may not be in the data dir) to
an specified install location.

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.

This obsconfig.h variable will be true or false depending on whether the
project is configured with the cmake UNIX_STRUCTURE variable or not.

Since we rely on the dynamic linker to find the library for us via
dlopen(), we need to have DL_OPENGL be .so.N, not the full library
filename, as ldconfig doesn't cache the full filename

Use of TARGET_SONAME_FILE requires the library to be marked as SHARED,
not MODULE

This closes pull request #370

Because libobs-opengl is a public library, it's customary to have SONAME
embedded in the library file.  Also remove the prefix override and
remove the prefixing "lib" from the output name.  This also requires us
to pass the library file name to dlopen invocations.

This improves dependency copying and adds separated debug/release
install files.

This is mainly intended to be used for preloaded/injected DLLs, which
don't belong into the libdir or plugindir.

CMake now works on all platforms