Fixed bug in FileSandboxResourceLocator

This was not handling paths with special characters in them correctly.
The CustomUriScheme class has been enhanced to deal with both raw
and decoded paths in a more specific fashion to help with this.
Delayed release of 1.0-M3

Sue wasn't ready to go live with one I had queued up on 12/02.
This cherry-picks the URI handling fix (6ef5f89) added afterwards.
It also includes a schema migration script to help going from M2->M3.