Created Dropdown and ABTest Cases

I added two new test cases for dropdown problems and A/B tests.
Fixed A/B selenium test case

The A/B test is now set up to verify that the .split-test-view element
(which contains the A/B test) is present and that the .outside-app
element (which contains our “There has been an error” message) is not
present.
Created a conditional test case

I created a conditional test case that checks if selecting different
responses causes different content to display in a subsequent unit.
Improved conditionals test & added to suite

I improved the conditionals selenium test case to handle slow loading
on stage, and added Conditionals.html to the test suite.
Added a reset function to Conditionals

I found that what was causing Conditionals to pass sometimes and not
others was that my response wasn’t being reset, so the wrong thing was
being read every other time.  Added a click css=input.reset command to
fix this detail.
Removed LTI from test suite

Since LTI has other issues that still need untangling (basic auth,
ssl), I’m removing it from the test suite so that I can merge the other
reliable tests.
Merge pull request #11 from Stanford-Online/mondiaz

Created Dropdown and ABTest Cases