added clickable regions so that users can click on the left/right arrows to advance by one (or one decimal place)
added modifier keys to allow the scrubber to move at different rates: +alt = 0.1, +shift = 10, +alt+shift = 1
subproject change
added aria roles to the left/right buttons on the slider, added comments to getExponent(), fixed code formatting
ImagePicker upgrade

Test Plan:
Run tests
Verify that imagepicker doesn't disappear on mouseout and the imagepicker lazy loads images
JS ImagePicker upgrades

Test Plan:
Run tests
Verify that imagepicker doesn't disappear on mouseout and the imagepicker lazy loads images

Reviewers: pamela, john, brian

Subscribers: #cs

Differential Revision: http://phabricator.khanacademy.org/D14114
T3297 - Check in thumbnail python script

Reviewers: pamela

Subscribers: #cs

Differential Revision: http://phabricator.khanacademy.org/D14140
Revert "subproject change"

This reverts commit f3795855e3f3f5f2c19c57e85b18b6572c25121c.
Merge pull request #186 from kevinb7/click_the_scrubber

Improve the usability of the number scubber