Decrease call to PluginManager in WGBukkit

If WorldGuard is already found we bypass the call to
the PluginManager and use a cached version.
Added MAX_PLAYER and MAX_PLAYER_MESSAGE flags
Allows setting maximum number of players in a region
and sends a message if a region is at capacity.
Fix players being able to plant cocoa beans in protected areas
Add enderpearl flag to prevent players from teleporting to/from regions with enderpearls
Added config setting and flag to block explosions by plugins.
Mob damage setting/flag blocks poison DoT
Fireball flag should block blaze fireball ignition too now
Fixes for tripwire, flower pots, wooden buttons, ender chests, and sneaking
Added config option to block zombies from breaking down doors
Added changelog for 5.7. Incremented version in pom.xml.
Fix enderpearl flag properly
Remove max players flag for now.
There are currently too many unhandled circumstances
which can easily break this flag such as players
entering region in weird ways (teleporting, falling,
logging in) and states changing. It is also horribly
inefficient at the moment.
[maven-release-plugin] prepare release 5.7
[maven-release-plugin] prepare for next development iteration
That was not in there
Fix region teleport permission
Fixed placing stuff in flower pots. (derp)
Move enderchest to use flag
Setting summary-on-start to false reduces much more clutter now
Merge branch 'master' into sakura

Conflicts:
	pom.xml
	src/main/java/com/sk89q/worldguard/bukkit/WGBukkit.java
	src/main/java/com/sk89q/worldguard/bukkit/WorldConfiguration.java
	src/main/java/com/sk89q/worldguard/bukkit/WorldGuardPlayerListener.java
	src/main/java/com/sk89q/worldguard/protection/GlobalRegionManager.java
	src/main/java/com/sk89q/worldguard/protection/flags/DefaultFlag.java