Use ReplSet instead of ReplSetServers in example

Use the updated name of the ReplSet class in the replicaset
documentation.

Closes #935.
sometimes db_command can be an array (e.g. [findandmodify query, getlasterror query])
Update Readme.md

Update run button to include more examples, and new features
Kerberos tests are passing
Cleanup of debug statements
More tuning of ha with mongos
Merge pull request #946 from Runnable/1.3-dev

Update Run button
Merge pull request #937 from evanp/issue935

Use ReplSet instead of ReplSetServers in example
Merged in missing setReadPreference #948
Moved _emitAcrossAllDbInstances to base
Added tracking of db instances across replset
More fixes to handle sets that never come back up during testing
Added huge insert and each test #950
Added test and fix for findAndModify with no chained getlasterror on w:0 and safe:false, #941
Merge commit '21c57fdec919b48439de08ab5ba84c7318a19373' into 1.3-dev
Fixes for gridstore close returning the gridstore object, added test #938
Ensure cursor.items is nulled out on toArray #936
Fixed history
Manually tested correct HA on primary down and up again with new priority
Fixed cursor test