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.
Update re module so that all / characters in Python input are escaped.
Implement hyperbolic trig functions in the math module.
bug fixes to urllib.request plus a test page.
Merge remote-tracking branch 'bnmnetp/master'
Update dist.