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.
rebuild skulpt
bug fixes to urllib.request plus a test page.
Merge remote-tracking branch 'bnmnetp/master'
Update dist.
modified m and test.js to exit with exit codes.
travis config file
Make set.js use correct boolean singletons.
Make pow() handle large integers as longs.
added simple 'document' module example
Merge pull request #108 from mrshu/master

Added simple 'document' module example
Merge remote-tracking branch 'rixner/master'
Update dist.
Add Sk.builtin.checkBool function.
Some turtle methods were returning old style javascript numbers, not numbers constructed to be Python objects.  See the error that is can cause in #110
rebuild dist
Merge branch 'master' of github.com:bnmnetp/skulpt