GXemul Code2

Minor README updates.

Minor documentation updates (separating the new from the legacy framework in the list of emulated machine types).

Updating the TODO.

When single-stepping, all state change (except for Custom StateVariables such as RAM contents) is now displayed.

Implementing pre-run-checks for M88K and MIPS cpus, for checking the r0 and zr registers, respectively.

Adding an "accuracy" variable to the RootComponent, which must be set to either "cycle" or "sloppy". Also adding some better error reporting during component deserialization.

Removing the "global time" concept. Adding a helper for debug message indentation.

The step command now takes an argument (default is 1).

Updating the TODO.

Interleaved execution of multiple components, running at different speeds, should now work.