time lapse video recording

[sbarber2]

This issue proposes that PlantTracer provide its own time-lapse video recording functionality.

There are multiple motivations for this enhancement:

1. We've been relying on users to record videos with their own time-lapse video recording app, typically using the Lapse It app on an iPhone (or iPad) (but could be an Android smart phone or tablet). Lapse It does not provide, according to Simson, the "time lapse rate," though the recording files do provide the frame rate, and we need to know the time-lapse rate. It would be nice not to have the user input that manually separately and/or incorrectly.
2. Ease of user setup -- if the functionality is included in the webapp, then the users or the project staff don't have to set up the recording program each time
3. Cost per user -- there would be no issue of having to license a commercial time lapse recorder
4. Consistency of file format -- if the webapp controls the recording and the production of files, there will be less functionality needed in the webapp itself to accommodate multiple video file formats
5. Less pressure for video editing functions -- Lapse It and other recording software sometimes include watermarks or branding trailers that require post-recording editing the of the videos. We don't want to make PlantTracer/webapp into a video editor if we can help it.

[sbarber2]

Initially assigning to @simsong to review and potentially the issue description. Please assign back to me when this is done.