SERVER-13635: make index check in sharding use listIndexes
SERVER-13635: use consistent method for checking capped size
SERVER-15294 add fileSize to db.stats() on empty db
SERVER-15549 listDatabases command should only list existent databases

The database information is split between the storage-engine database
catalog and the database metadata, which could potentially be in-memory,
but not created on disk yet. The cases where this happens are only
applicable to the Admin database.

This change makes the listDatabases command only list databases from the
storage-engine's catalog.
SERVER-15547 removed legacy tools from source tree and build configuration. make use-new-tools option a no-op
SERVER-15502 simple targeting of explain for writes in mongos

Further command refactoring postponed
SERVER-14668 ignore empty options returned from listCollections in dumprestoreWithNoOptions.js
SERVER-15555 dynamically import pymongo in smoke module only when needed
SERVER-15425 Remove nodes from the _slaveInfoMap when they are removed from the replset config
SERVER-15547 removed tests that rely on tools --dbpath option