Huge code changes, backup your data before update.

Add:
1. Queue support for shop and database actions.
2. Unlocked the chars limit.
3. Stats for shop loading, now you can see how long time to load a shop(avg)
Fix:
1. A MySQL bug
2. Throw NullPointerException for update checks when SpigotMC.org server down.
3. Update message use WARNING log level.
4. parseColour called after some messages already printed out.
5. Multi called signSetText.
Optimize:
1. Queued shop and world actions can improve the performace on huge server.
2. Rewrited shop loader have better performace to load shops, they can let server boot speed faster.
3. Removed some dupe checks and setSignTexts, this can improve some performance.
4. Queued databases can caching the SQLs waiting some times flush in database in once not one one one and another one make server lag lag and lag.