Allow classes to create an iterator over an internal list.
Add test case for iterators.
Update dist.
Add __iter__ to tuple and dict.  Update tests.  Rebuild.
Merge pull request #141 from albertjan/travis-setup-3

Travis setup 3
update access token for skulpt
update dist-update.sh and update index.html
cleaned up .travis.yml
Merge pull request #143 from albertjan/travis-setup-4

update dist-update.sh and update index.html