Added multi-tasker for multithreaded task handling

Signed-off-by: Irmo van den Berge <bergerkiller@gmail.com>
Merge pull request #489 from bergerkiller/master

Added multitasker class to handle multithreaded processing of tasks
Thread annotations move
MultiTasker update to use enums and indicated that start/stop/finish are not thread safe
Made multitasker class more versatile, not restricting to runnables

Signed-off-by: Irmo van den Berge <bergerkiller@gmail.com>
Merge pull request #490 from bergerkiller/master

Made task handling part of the multitasker class itself
Retry file write when a ClosedByInterruptException is thrown
More protection for ClosedByInterruptException
more ClosedByInterruptException handling
Added delete method to SimpleRegionFile
Missing method
Add InputExecutor to execute input each frame
BAAWrapper fix - also LFCR issue
Added custom view volumns for observers
Added support for entire Region BiomeManagers
- WrappedBiomeManagers wrap a 16x16 array of chunk BiomeManagers
- Fixed a bug with CuboidBuffers
Added a SetQueue for handling Dirty queues
Headers
Changed PluginDescriptionFile to use YamlConfiguration instead of
directly using snakeyaml.
Added YamlConfiguration(Reader) constructor.