Allow loading of simple local extensions from
extensions/local/{author}/{extension}/
Only try loading local if the directory exists

Signed-off-by: Gawain Lynch <gawain.lynch@gmail.com>
Wrap a try/catch

Signed-off-by: Gawain Lynch <gawain.lynch@gmail.com>
Merge pull request #1847 from GawainLynch/hotfix/local-extensions

Allow loading of simple local extensions