DATAMONGO-957 - Add support for query modifiers.

Using Meta allows to the define $comment, $maxScan, $maxTimeMS and $snapshot on query. When executed we add the meta information to the cursor in use.

We’ve introduced the @Meta annotation that allows to the define $comment, $maxScan, $maxTimeMS and $snapshot on a repository finder method.
Added tests to verify proper invocation of template methods
Use DBCursor.copy() for CursorPreparer.

Original pull request: #216.