Add tests to CI

[hswick]

Currently travis only runs this test https://github.com/TrueBitFoundation/webasm-solidity/blob/master/test/judge.js

We need to add continuous integration support for the newly added tests such as:
test/task-lifecycle.js
test/task-lifecycle-ipfs.js
test/task-alphabet.js
test/task-alphabet-challenge.js

This will also involve adding ipfs to travis because all the tests above (beside task-lifecycle) depend on it.