This PR is aimed at improving visibility of defines and variables, i.e., make variables static where possible and only have necessary defines in header files.
Also adds const keyword where possible.
Lastly, removes redundant switch case for key handling.
This PR is aimed at improving visibility of defines and variables, i.e., make variables static where possible and only have necessary defines in header files. Also adds const keyword where possible. Lastly, removes redundant switch case for key handling.