Positional Audio breaks on public TS server with 1000+ users

[jhakonen]

The shared memory protocol that Tessumod and Tessumod Plugin uses to communicate with each other writes TS user's client id to a signed short value (max 32767), but in reality the value can be higher than that.

This will cause an error like this:

2020-06-05 23:51:15.295: ERROR: [EXCEPTION] (scripts/common/Event.py, 46):
Traceback (most recent call last):
  File "scripts/common/Event.py", line 44, in __call__
  File "/res/scripts/client/gui/mods/tessumod/positional_audio.py", line 80, in enable
  File "/res/scripts/client/gui/mods/tessumod/positional_audio.py", line 156, in on_update_to_ts
  File "/res/scripts/client/gui/mods/tessumod/mytsplugin.py", line 95, in set_data
error: short format requires SHRT_MIN <= number <= SHRT_MAX

Should probably be fixed as part of #32 .