Added failing test for GetRange() + Take() + Reversed() that should not overflow
Fix Test_Can_Bulk_Insert_Raw_Data() unit test that was failing on slow hosts

- need to wait for the last progress notification, because it is invoked asynchronously
- added a note in the XML docs to remind that progress.Report(x) may be called after the task has completed
FdbKeySelector now implements IEquatable<FdbKeySelector> as well as the == and != operators
Added a bound check step in range queries when the currents bounds are not equal to the original range.

- call GetKeys(...) to resolve to actual keys, and bound check them before starting the range read.
- this should fix the overflow bug for non typical queries that mix Take(), Skip() and Reverse()