SERVER-6400: do not call FieldRef::getPart on non-existant parts
make test work even if system can't handle a lot of connections
SERVER-6400: nice construtor for NotMatchExpression
SERVER-6400: fix $or use of indexes
SERVER-6400: comments
SERVER-6400: This switches from MatcherOld to Matcher2
             This commit also has all semantic changes encompassed in this switch
SERVER-6400: additional update test
SERVER-6400: inprog has a $all option which isn't valid syntax, so re-write without
SERVER-6400: change error codes agg is expecting
SERVER-9713 Port some BSONObj accessors to accept StringData

Accessors ported:
- getIntField
- getBoolField
- getStringField
- getObjectField
- operator[]
- getFieldUsingIndexNames
SERVER-9713 Rewrite BSONObj::getFieldDotted to accept StringData
SERVER-9702: debugging for drop2 test failure