Update sts_commons_forum.module

Reworking the 'if ($node->type == "group"' bits to use the OG method: og_is_group_type($node->type).

Also, re-indented the file so that it conforms a bit better to coding standards.
Merge pull request #1 from teglia/patch-1

Reworking the 'if ($node->type == "group"' bits to use the OG method: og_is_group_type($node->type).

This allows the module to work with content types that are not named "group" but are still OG 'groups'.

Also, re-indented the file so that it conforms a bit better to coding standards.
sts_commons_forum.module