Added slaveOk support to ConnectionString

JAVA-1433
Equality support for MongoClientURI

JAVA-1472
Removed unnecessary final declarations in codec interfaces
Removed Jira refs in ConnectionString
Removed support for explain in MongoCollection and removed all model classes that existed solely to support it.

JAVA-1491
Fix or suppress compile warnings
Remove unnecessary final keyword
CreateIndexSpecification fixes for 2.4
Fix codenarc highlighted groovy error
Criteria now required for Find and Count

JAVA-1492