Move system specific features into sys module
This organizes the system specific code into two modules, redox and unix. Tests are moved when necessary to the root, so they can be run on both modules. Termios is implemented for raw mode on Redox.
This organizes the system specific code into two modules, redox and unix. Tests are moved when necessary to the root, so they can be run on both modules. Termios is implemented for raw mode on Redox.