Dropped ServerSoundParams -> moved to ServerPlayingSound. This gets rid of the duplicated
'fade' and 'pitch' values on server-side where only one was used anyway.
SimpleSoundSpec is the basic sound without positional information, hence 'loop' is included.
Recursively added PROTOCOL_VERSION to most functions to reduce the versioning mess in the
future. Per-type version numbers are kept for now as a safety rope in a special case.
* Modernize lua read (part 2 & 3): C++ templating assurance
Implement the boolean reader
Implement the string reader
Also remove unused & unimplemented script_error_handler
Add a reader with default value
* squashed: CSM: Implement register_globalstep
* Re-use fatal error mechanism from server to disconnect client on CSM error
* Little client functions cleanups
* squashed: CSM: add core.after function
* core.after is shared code between client & server
* ModApiUtil get_us_time feature enabled for client
