Added a shift-list property to caps word to allow adding more keys to
be shifted aside from alpha keys.
Added a &prog_word behavior, which is the same as &caps_word, except it
adds MINUS to shift-list (this matches QMK's caps word behavior).
Added a no-default-keys property to caps_word, which removes the
implicit alphanumeric keys from continue-list and shift-list so you can
fully customize the lists.
Also adjusted the default continue keys to include numpad numbers,
since those are numbers too.
Removed "label" properties which no longer have any function.
Labels are still used as layer names and as identifiers for sending
behaviors between sides of a split keyboard, so those have been left
alone for now.
