Just some cleanup work

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2849 86ba831e-150c-0410-ab35-e06eaae15ed9
* Tracking of current environment in high level sound engine
* Notification of environment change to reverb engine
* Notification of active reverberation to low level sound code
* Minor cleanup in z_native

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2850 86ba831e-150c-0410-ab35-e06eaae15ed9
* Nine environmental reverb presets defined in base/sounds.edf
* p_testenvironment console command added

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2851 86ba831e-150c-0410-ab35-e06eaae15ed9
* Bug fix: always update reverb engine EQ when changing environments
* Tweak "corners" of 3-band EQ to 250 and 4000 Hz
* Fine-tuning of presets for better differentiation between "bright" and "dark" environments.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2852 86ba831e-150c-0410-ab35-e06eaae15ed9