Includes proper string representation.

Also made some initial timer validation.

Makes use of the `Error` enum to handle errors. This is a better way to handle errors in Rust. It is also more idiomatic.

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.

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

Allowing better directory usage.
Created initial printer file.

The complete GB, CPU and MMU linking is done.

Uses the `build.rs` file to generate compile time information about the build environment.
This information is exposed to the WASM environment through interface methods that are then used by the `Emulator` interface.

This reverts commit e252646f.

Adds an extra EOL.

Better debug support with feature

Added boot roms to separate dir
New static boot roms