Out ta Get Me - Sprint 4 Completed

Note: There is no disk image for v0.12 because of a discovered bug. Instead use the disk image for v0.12.1.

For detailed changes, see this blog post and Sprint 4 milestone.
QA Performed by @antonmolodykh.

New features

• Adds automatic API documentation (#588)
• Adds Add API call for next/previous (#591)

Bugfixes / improvements

• Migrated to Flask (#611)
• Inherited network configuration from NOOBS (#609)
• Fixed the problem of detecting a network connection on Raspbian Stretch (#624)