Help with keyboard for BangleJS2 - Multitap/T9 layout

Thanks for the tip! Just opened a pull request.

Can be tested here. Code here.

Small bug:

• The font on the ok-button in help message changes to be smaller when pressing it - I think it's to do with loading the layout which has a smaller font on buttons. Maybe.
  
  

Suggested future improvements:

• wrap the text field in another way so that all available space is always used independent of character widths. Now the displayed string is fixed to a specified number of characters.
  
• maybe align buttons perfectly in the button layout. (this is nitpicking)
  
• maybe make the marker blink.