brython/ast: function and class decorators.
Merge pull request #63 from texcoffier/master

Regression tests framework
Merge pull request #64 from texcoffier/master

The regression tests use 'node' javascript interpreter if installed
fixed %s string replacement, fixed iterate over string in javascript mode.
Brython AST: elif/else statements are properly inserted into .orelse of IfExp ast node.
core: deprecated javascript mode "{mylabel:XXX}" - now labels must be quoted: "{'mylabel':XXX}"
fixed javascript mode `dicts` to allow them to use classes and instances as keys, using a ternary_operator hack.
core: fixed javascript mode "a[ Object ] = XXX"
Brython AST: for loop ast node
import of Brython's py2js.js
Brython: updated ast.py to support: while loop and augmented assignment.
exposed $tokenize in py2js.js
updated server.py to use forked py2js.js
added support for @classmethod
new support for @staticmethod
brython ast: support UnaryOp
brython ast: support for Not, List, and Tuple ast nodes.
brython ast: Dict ast node, and fixed Str ast node.
brython ast: added support for Subscript ast node.
brython ast: support for simple slices "a[1:2]"
brython ast: support for slice with step "a[n:n:n]"
brython ast: binary and unary operator classes
brython ast: support Import and ImportFrom, testing translating python_to_pythonjs.py with Brython-to-AST binding.