Adds this CPU speed print support to the web debug panel.

In some versions of WASM-bindgen the re-setting of the hook from the current panicking thread would fail.

This makes it possible to select CBG or DMG mode taking into consideration the CGB flag in the ROM file.

There's also support for the disable operation.

Support for Game Boy Color (CGB) 

Closes #8

See merge request !16

With initial approach for scalling down the speed of other components.