Plugin expansion

[alhom]

Expanding beyond the barebones vslv reader interface. So far, here is a wrapper for a vlsv database, that can extract good time information as long as "Try harder to obtain correct times" is checked.

Todos:

• bounding boxes extraction for write-rank domains to use for building interval trees
• ... find what useful settings can be forced for vlsv, like "Treat all databases as time-varying"