Requesting 2 more seconds for video feed every trial

[ananthamurthy]

For all sessions, could we record for 2 additional seconds before terminating any trial's video recording
We want to be able to see how the eye-blinks end

[dilawar]

@ananthamurthy I am going to merge branch Hrishi into master branch tonight. I've created branch BeforeShock which is today's master branch after fixing #51. Please switch to this branch to use today's code.