Proper distribution package for csound~

[vlazzarini]

Currently the csound~ object is distributed as archives with a lonely binary object. This is bad because the archive doesn't contain help files and examples. I checked the frontends/max_csound_tilde directory and found all this stuff there. Also I found scripts which build .msi and .pkg installers which were deprecated in favor of packages. Max package is essentially a directory with defined structure, containing such subdirs as extras, help, etc. Having a proper package we can submit a package to the their repository, and users will be able to install csound~ from the Max itself through the package manager.

I checked how the build process is done, but unfortunately I don't know CMake well enough to make modifications that would collect all assets into proper places.

From csound/csound#696

[gogins]

To build a package one uses CPack, a separate program that is part of the CMake distribution, and the CPack configuration is written as part of the regular CMakeLists.txt file. Then one runs cpack to produce releases in a wide variety of formats. See https://cmake.org/cmake/help/latest/module/CPack.html. There is not a CPack generator for Max packages but the CPack commands and configuration variables provide all the control necessary to produce a Max package.