Fixed a couple of mistakes in the JavaDoc.
Incremented to 2.1.1-SNAPSHOT for development towards the next version.
Fixed a bug causing the entity modifier to always lookup the same world

The entity modifier would try to cache each equivalent converter by its
specific type - i.e. whether or not it converts entities or watchable
collections - but this isn't enough to distinguish entity modifiers 
as they store a hidden reference to the world the entity is supposed 
to be occupying. 

Thus, after the first entity modifier is used for "world", it would 
be subsequently cached for every world ("world_nether", "world_end", 
etc.). The end result was that entity modifiers would only work for 
one world.

This patch fixes this problem by adding a proper equals() method to
the entity equivalent converter class, along with all the other 
equvialent converter classes, in case it should prove to become useful
in the future.
Automatically delete empty JAR-files left over from upgrades.
Don't reference classes by name - it is not safe.
Improved the fuzzy reflection system tremendously.

It is now possible to specify exactly what method or field you're
looking for, based on a number of different critera such as return
value, parameter count or parameter type, exceptions, modifiers, name -
all using a very fluent builder syntax.
Improve JavaDoc and add the ability to match declaring class.
Attempting to add support for MCPC.

Still have to track down a very elusive bug however.
Fix a serious bug that caused Blocks to inadvertanly be created.

Our custom IOC system (DefaultInstances) would call new Block(0) on a
MCPC based CraftBukkit system, causing air blocks to be treated as 
solid blocks. We prevented this by explicitly forbidding it from 
creating instances of ItemStack or Block in our structure modifier's
default field generator.

A second bug was caused by mismatched methods in WrappedDataWatcher,
which we solved by simply trying to use them, and then swapping them 
if we encounter any errors or weird state.
Make it possible to send and recieve packets during login.
Inform the server operator about problems with Guava.
Make people aware of NULLs in the StreamSerializer class.
Moving fuzzy reflection "framework" to a seperate package.
Add getters and setters for each of the fuzzy contracts.
Improve the toString()-functionality of each fuzzy contract.
Add an equality and hashCode() method to all the matchers.
Use isMinecraftClass to check for NMS classes.
Moved packet-related classes to a seperate package.

This is backwards compatible because they were all package private.
Make it possible to specify a custom incoming packet interceptor.
Made the constructors for the different injectors more generic.

We now use builders. This should make it simpler to introduce Netty
Spigot support.