on "next/back" transition through the map and only then start the next fragment

[mushon]

right now it starts playing the next video, flies the map, but transitions to the next segment only at the end. order should be:

1. click next
2. old fragment slides out revealing the map under it
3. map flies to focusing on new "pulsing" location
4. new fragment slides in over the map
5. if time-based (video/audio) play now

[mushon]

Also, during the geo transition, also transition the timeline (this hopefully will account for #60)
Optionally @akariv: what if we scale transition durations by relative time gap?