minor: remove hidden Examples headers

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1492 sh.moveChunk, sh.shardCollection, sh.waitForBalancer, sh.waitForPingChange

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1492 db.addUser, db.cloneCollection, db.copyDatabase

Signed-off-by: Sam Kleinman <samk@10gen.com>
minor: edits