iOS support, and a host of fixes/improvements

Sorry for the giant pull request.

Everything under contrib is related to iOS support.   A lot of this required making function names unique since iOS doesn't support dynamic libraries. Subtle changes from Cocoa imports to Foundation (as the former doesn't exist on iOS).  NSRect to CGRect, etc. And a new copy of ffi with iOS support.

Under src/newt_core this contains some bug fixes:

VM byte code make-frame, NewtObjRemoveSlot, NewtRefToInteger, SubStr, NcDivide, NcBAnd, NcBOr

And some added functions:

Array(size,initialValue), StrPos, StrReplace, ExtractWord, Ref, RefOf, Negate, SetContains.

All of these bugs & added functions were realized while trying to run ViewFrame's decompiler inside the NEWT/0 environment.