Fdb.System.EstimateCountAsync() can take an IProgress<T> to report progress when counting very large ranges
Test Commit, Please Ignore

- This is a totally legit commit, there is nothing particular about it.
- This is not the commit you are looking for. Please move along.
</COMMIT>
- Added cheaty way to bypass the InvalidOpEx you get when getting the Key of a Directory Partition
FDBShell: refactored and added more commands

- version, status, show, topology, shards, ...
- sampling now works on the current directory
- more to come!
FDBShell: now comes with even less build breakage!