FEAT: added preliminary implementation of object! datatype.
FEAT: implemented actions for object!: MAKE, FORM, MOLD.

MAKE on object! only supported in interpreter for now.
FEAT: path evaluation is now spread over datatype-specific code instead of centralized in the interpreter loop.
FEAT: added new (internal) action: EVAL-PATH
FEAT: path read/write access now supported for objects (interpreter).
FEAT: added CONTEXT mezzanine.
FEAT: object's functions can now be called using path notation.
FEAT: centralized new series allocation in trampoline action for COPY.
FIX: series pointer not refreshed after possible reallocation.
FIX: ensures that words stored in context are of type word!.
FEAT: added COPY support for objects.
FEAT: now objects can be constructed from other existing objects.

Note: functions are not rebound yet in new copied objects.
FEAT: functions' bodies are now correctly rebound in new objects.
FEAT: correct indenting of nested objects when MOLDed.
FEAT: added SELF keyword support for self-referencing objects.
FEAT: added new mezzanines: WORDS-OF, VALUES-OF
FEAT: now object! implements REFLECT action for 'words and 'values selectors.
FEAT: added support for REFLECT 'body selector on objects.
FEAT: MAKE on object! now supports a spec argument of type object!.

make <proto> <spec>

<proto> is the base object that gets copied and extended with a rebounded copy of <spec>.
FIX: made words reference contexts less directly (GC-compliant way).
FEAT: added IN native.

Note: only tested on objects so far.
FEAT: make ctx member in red-function! overlap with ctx in other type structures.
FIX: function bodies were not copied before rebinding.
FIX: functions were not properly recreated during a rebinding in objects.