Release to use the new OS4 module

This release generalizes the system extensions used so you will need to load that as a separate module (https://github.com/hth313/OS4).
You will need module hardware or an emulator that implements bank switching independently between page 4 and the application module pages (8-F). If your hardware does not support it, try the previous 0C release instead that does not have this requirement.

• Some minor changes have been made to the keyboard layout.
• Some new functions are added in this release, =I, ≠I, <I, <=I, <>I and VIEWI.
• PSEI has been removed (use PAUSE in the Boost module instead).
• The clock now works properly when Ladybug is active.