Fix setup issue and remove region expansion

This commit consists of two components:
- Restarts are no longer required after setting up the first arena
- Regions no longer auto-expand

The restart requirement is fixed by preventing the ArenaMaster from
actually creating an Arena object and assigning it to the selected
arena upon generating the default arena node in the config-file. The
problem was that the selected arena was set to this initial Arena
object, but another Arena object was created afterwards, which due
to the equals() method of ArenaImpl overwrote the previously created
Arena object in the arenas-list, but didn't change the reference in
the selected arena. In other words; two identical Arena objects were
created, but used in different places (arena list vs. selected arena).

The auto-expansion is removed by simply never auto-expanding regions
upon setting the arena warp or spawnpoints. Instead, setting these
warps throws an error, if p1 and p2 have not yet been set, or if the
location is outside the region.
update ClassLimitManager to provide a set of names of Players who have picked the provided ArenaClass. This will allow manipulating players of just a certain class more easily than before. One possibility is (mind you this is NOT implemented) adding potion effects to a class
Merge pull request #194 from acstache/bleeding

Keep track of which players picked which class

- Change MutableInt counters to String sets of player names
- Add getPlayersWithClass() method
Fix default fixed waves.
Some 1.6 updates...
Merge branch 'bleeding' of github.com:garbagemule/MobArena into bleeding
Use item number for hay bales until 1.6
Leave out 1.6 stuff until a stable release.
Update plugin.yml towards next release.
Fix the region setup bug.

Previously, the set() method would overwrite coordinates completely
without min/max'ing the values to preserve the invariant that p1 is
the lowest point and p2 the highest.
Version 0.95.2

Hotfixing region issues.
Update plugin.yml towards next release.
Change the way region setting works.

The region now contains two location references per region point for
the bounding boxes where p1, p2, l1 and l2 remain the same (min/max),
but also additional locations for the player's actual location, such
that e.g. moving back and re-setting a point has the more intuitive
behavior of expanding regardless of the optimized points.

This also (hopefully) finally fixes the previous issues with the setup
process *knock on wood*.
Version 0.95.3

- Make the region setup more intuitive
- Fix the lobby region issue
- (Hopfully) fix the setup process
Update plugin.yml towards next release.
Add time trial timer setting to config
Don't automatically register permissions for arenas
Merge remote-tracking branch 'upstream/bleeding' into bleeding

Conflicts:
	resources/plugin.yml
	src/com/garbagemule/MobArena/ArenaImpl.java