Squashed commit of the following:

commit 7f9ed3ce5b9fffecb8d13aec14dd4721b2f7c293
Merge: b7f0cc6 c7dd525
Author: Kolier <kolier.li@gmail.com>
Date:   Fri Aug 29 15:59:31 2014 +0800

    Merge commit 'c7dd52558eec3c57b7012df653e7641033b952b5' into 7.x-1.x-2014-08-29

commit c7dd52558eec3c57b7012df653e7641033b952b5
Author: Kolier <kolier.li@gmail.com>
Date:   Fri Aug 29 15:59:31 2014 +0800

    Squashed 'modules/feature/topic/' changes from 5dbec9f..75afa57

    75afa57 === 7.x-0.2 === New: Relation: Master. New: Relation: Slave. New: Make Node: Topic as OG: Group. New: Make Node: Subject as OG: Group Content. Mod: Use safeword.module instead of machine_name.module to generate machine readable text.

    git-subtree-dir: modules/feature/topic
    git-subtree-split: 75afa57d53dd2674066373570cc975e8270fcfe6