inverted the entities for weld (before that the clicked entity got deleted upon sound emitter removal)

fix fadeout not working when play length is infinite

Fade-out is now incorporated into play length: a X seconds long sound with Y seconds fade-out will fade out X-Y seconds after the sound started, instead of X seconds.
Fixed a few things with stop timers conflicting due to fade-out, ...
Some menu changes (mostly tooltips)

- fixed sv cvars not present on client
- added proper sv cvar flags (notify client on change and stop client from editing + send server cvar value to client)

Add fade-in and fade-out duration options

Fixed some tooltips

- Replaced 'Loop' option with 'Loop Length' which is now differenciated from 'Play Length'
- Added 'set loop length to play length' option
- Added 'use soundscript pitch' option
- Added 'toggle always plays' option
- Menu revamp to add all new features and more
- Context menu property editor rework
- Auto length now calculates sound length per sound and per random pitch in soundscripts
- Some other changes...

- removed a print

- Add DSP 36 and 37 for the forbidden dsp convar
- Menu sound preview now plays the pitch set by the player for soundscripts, and the same for volume, for all sounds.

- Change max sound level in multiplayer from 90 dB to 100 dB