ami changeover facilitation

whether to accept new sessions or terminate an instance will also consider recentness of the image.
fix image version stats display
fix redirection after google drive auth

ref #136
Volume creation is threadsafe now.

Async daemon refreshes status before creating new volumes.
use image ver 0 where naming scheme isn't followed
reorganize ebs backup and detach sequence

to avoid possible snapshot corruption
renamed bkup to jboxd
wait for container backup before starting new

If a user logs out and tries logging in immediately,
wait till the earlier session is backed up so that changes
made in previous session are visible in the new session.
Merge pull request #138 from tanmaykm/tanmaykm

multiple deployment and stability fixes