Clean up type-checking in builtin functions to match Python.
Add missing nb$add and nb$inplace_add methods to list, tuple, and string objects.
Call nb$add methods of sequence types when using a + operator.
Make sum handle non-number objects and throw errors like Python.
Add missing nb$multiply and nb$inplace_multiply methods to list, tuple, and string objects.
Call nb$multiply methods of sequence types when using a * operator.
Test case to check user-defined operator overloading methods.
Fix builtin pow function to properly handle nmber and lng objects.
Avoid spurious failures of t422.py.  Could it really be that different coprocessors will occasionally cause this test to fail even on the same machine?
Modify the urllib from web cat's branch so that it works with a simple synchronous xmlhttprequest object.
Merge branch 'master' of github.com:rixner/skulpt into rixner-master
Merge branch 'master' of https://github.com/bnmnetp/skulpt
Add an external configuration variable Sk.inputfun.  This can be configured similar to the Sk.read variable for importing files.  It is backward compatible with the current practice of using prompt.
Implement use of keyword arguments for __init__ methods.
Pass through all argument types to klass, so they will work correctly
with __init__ if they are implemented later.
Fix type built-in function output to use 'type' or 'class' correctly.
Update re module to handle syntax like Python instead of Javascript.

Javascript does not recognize {,n} as {0,n} like Python does.
Whereas Python will match "pattern$" with "pattern" and "pattern\n",
Javascript will match with only "pattern".
Improve regex introduced in previous commit to fix re module syntax.

New regex prevents matching with '{,' when those characters are included
in square brackets or are escaped, so that Skulpt replaces '{,' with '{0,'
only when the characters are being used as a modifier.
Make isinstance throw TypeErrors like Python for invalid arguments.
Update re module so that all / characters in Python input are escaped.