CSHARP-956: Aggregate command with $out cannot be sent to secondary.
CSHARP-950: For GeoJson $near queries $maxDistance goes inside $near.
CSHARP-950: Added integration tests with the server.
CSHARP-950: Skip GeoJson integration tests when connected to older servers that don't support GeoJson.
Fix unit test that was failing because it sometimes couldn't read its own writes.
adding empty release notes.
CSHARP-959: wnote and jnote no longer throw errors on pre 2.6 servers.
CSHARP-961: Add error message when deserializing a nominal type that is an interface and there is no discriminator to determine the actual type.
Revert "CSHARP-959: wnote and jnote no longer throw errors on pre 2.6 servers."

This reverts commit 10cfbadd6bcee0cf5c7031a7baa5f118c7f59922.
CSHARP-959: don't recognize wnote or jnote as errors.
Fix another unit test that was sometimes failing when it couldn't read its own writes.
CSHARP-963: Support $date with ISO8601 string in extended JSON.
CSHARP-962: Add SetBits to IndexOptionsBuilder.
Added 1.9.1 change logs.
Added release notes for 1.9.1.
CSHARP-970: Correct doc comments for GetDatabase.
Bumping version post release
CSHARP-980:fixed issue with Kerberos corrupting managed memory.
CSHARP-993: Ensure unique ObjectIds across AppDomains.
CSHARP-986: Allow $external as a database name even though it contains a "$".