Merge tag '3.4.0' into develop

3.4.0
start 3.5.0
corrective seeking - seeking past a point where an ad hasn't been watched, will return you to the point of the ad you haven't watched.
throw error on undefined event names.
fixed dependency issue.
bower version number. bump in gruntfile.
unit tests for ad time ranges
fix unit tests.
update README.md
fix placeholder show at the end of content by adding an option for the destroy method to leave the element intact.
by default, don't hide controls during ads (fullscreen is gone, and we have corrective seeking working).
removing testem.json since tests are run with grunt-testem.
removed mrss tests since they're not set up yet.
using constants for config props (since I had a typo, and that shouldn't happen).
updating History.md
Merge branch 'release/3.5.0'