Secondary key actions

[nkrusch]

Received this feedback

It would be nice to have enhanced long-press options as e.g. special characters. Long pressing g for example is dead but could produce a & as in other keyboards. Changing the time a long-press takes would also be desired and easy to make real. (User defined slider from say 0 to 500ms instead of a fixed value x). I really like the privacy concept and there is no problem with no autocorrect. One could start a sentence with capital letters tho.

TODO:

• [ ] add secondary actions to more keys
• make long press time customizable (opened separate issue) → #88
• (duplicate) capitalize sentences → #59