Initialize Default Dargon Repository (C#).
Initial spike of libvfm.

Warning: SectorCollection doesn't yet fill blank space with null sectors!
Properly handle reading from Virtual Files with gaps between sectors.
ReadAcrossSectorsTest now has middle sector which is completely read from, so that all possible combinations of reads are now performed in unit tests.

- Combinations consist of: read nothing, read all, read left, read right, read middle.