Added tuple.__new__ accepting an iterable + tests

Support added to initialize a tuple using the tuple type class.  Allows
creation specifying positional or using the keyword argument 'sequence'.

Accepts iterables- tested with lists, tuples, sets, dicts and strings
Removed boxStrConstant, uncommented a few tests
Merge remote-tracking branch 'upstream/master' into runtime

Conflicts:
	src/runtime/tuple.cpp
	test/tests/tuples.py