Also fixed frame global memory issue in libretro.

Running under a single call.
This required increasing variable size from u8 to u16.

Created infrastructure that allows the usage of the serial device to capture the result of the tests.
Then the test is executed agains a pre-defined number of cycles and the result is compared against expectation.

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

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.

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

Allows the transfer of data according to the specs in dma.rs.

This is only a structure change and no real DMA implementation has been done.

The performance should be poor as there're lots of if clauses.

This is a temporary hack until a real speed switch is available.

The double speed mode is still not available.