Started work on making built-in types more lightweight:
- Created BuiltProcess to hold a single prototypical behavior used for
slot accessing.
- Extended IntegerProcess from BuiltProcess.
- Changed integer prototypical behavior to be a Java field.
- Changed boolean true and boolean false to be Java fields.

Signed-off-by: Jakob Brandsborg Ehmsen <jakobehmsen.github@gmail.com>