PortMedia Code

Modified CoreMIDI message rate limiting and now they only apply to IAC bus.

fixed some test programs, improved error messages from windows when port is opened by another application.

Fixed some edits to compile on Linux.

Incorporate changes after a review of 4583 related files from github, after reducing changes to 33K lines of diff in 219 pair-wise file comparisons and 476 unique additional files. Obviously, I will have missed some changes, but I found a few things of interest. Since this is such a large change with a lot of cleaning for consistent types, I also cleaned up some formatting conventions that always bothered me. At least the style is more internally consistent, but I've kept the PortAudio-like function naming style (e.g., Pm_WriteShort) so the API is almost unchanged (an int32_t was changed to the equivalent PmMessage). This is untested and only compiled on macOS. Next step is test over a high-speed USB loopback, which is waiting on some parts to build the needed hardware.

Delete pm_mac.xcodeproj from repo - use CMakeLists.txt to (re)build this.

Deleted all .vcproj files - these should be generated from CMakeList.txt.

Ported to Windows. Minimal testing. Ready now to integrate and test some pending updates and patches.

Updated pmmacosxcm and pmwinmm to use the new naming conventions of api_info and info for api-specific data. Compiled but untested on macOS, not even compiled yet on Windows, but that is next.

Implemented CreateVirtualInput and CreateVirtualOutput on linux. Changed "descriptor" to "api-info", so this needs to be changed for macOS and Windows. Added pm_test/README.txt with detailed description/checklist for running tests.

Adding missing files.