CMS/Gameblaster: add sbtype=gb, fix base addresses other than 220h, fix lack of sound when starting from autoexec, add autodetection (Thanks robertmo and Cloudschatze)
This commit adds a mediator class to decouple the CMS emulator from the engines
that use it. This allows for easier updating or replacement of the emulator or
addition of new emulators. It also enables using the emulator via a callback
mechanism.
The CMS emulation assumes the chips run at 8 MHz clock,
but in PCs they run at 7.15909 MHz, so the emulated pitch
is too high. Adjusting the requested sampling rate higher
by matching amount the pitch is lowered down to normal.
