Make Skulpt treat booleans like numbers.
Update builtin methods to return Python (not Javascript) objects.
Update set object methods to return Python (not Javascript) objects.
Make Sk.builtin.str.prototype.tp$richcompare more efficient.
Throw exception when attempting to multiply sequence by non-integer.
Fix calculation of slice indices.
Fix handling of negative indices in list insert.
Make skulpt handle booleans as numbers in binary ops, math methods.
Make trunc return an int.
Fix map to work properly with all functions.
Fix filter to work with builtin functions.
Make reduce use callsim instead of circumventing function call setup.
Add missing variable declaration.
Make unary ops on numbers return objects of the correct type.
Make slices throw a ValueError if given zero for step parameter.
Add optional slice arguments to list.index
Merge branch 'debug'
Merge branch 'nmber'

Conflicts:
	src/long.js
Merge branch 'js_return'

Conflicts:
	test/run/t512.py
	test/run/t512.py.real
	test/run/t514.py
	test/run/t514.py.real
	test/run/t514.py.real.force
Make user-defined objects return the correct true/false value.

From the Python docs, the following should be considered False:
"instances of user-defined classes, if the class defines a nonzero() or
len() method, when that method returns the integer zero or bool value False."