Java Edition 1.7.10-pre4

1.7.10-pre4 was released to provide further upgrades to Realms.

Additions

 * The ability to upload one's own worlds to Realms
 * An option to allow the Realms owner to enable command-blocks

Fixes
2 bugs fixed
 * Some possible future-compatibility issues
 * – Realms Player activity screen squashed to bottom