In evaluation logic:
- Added implementation of ProcessFactory in CustomProcess and added
passing of this to invocations of callable.
- Added prototypes for Closure and Behavior.
- Added support for calling BehaviorProcess's.
- Changed evaluation logic of EXEC_ON_FRAME to use BehaviorProcess
instead of CallFrameInfo.
- Added evaluation logic of LOAD_BEHAVIOR instructions.
- Added linking to Closure prototype in SP_NEW_CLOSURE.


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