Fix a small issue for [12361]
Fix a comment of [12358]. Thx to Reamer for pointing
[12363] Add condition support to vendors

Add new collumn `condition_id` to tables `npc_vendor` and `npc_vendor_template`
This is expected to be usefull to ie limit supplies for a holiday and similar restrictions
[12364] Some small changes

* Replace Expansion related magic numbers
* Remove an unneeded double line. Thanks to Ambal for pointing
* Add additional check for DK starting zones map file

Signed-off-by: Schmoozerd <schmoozerd@cmangos>
Remove another redundant InBattleGround() check