Update the Forge implementation

This PR is to update the Forge implementation to the new MCP names, add a buildscript to automatically generate a jar file, archive it through maven and fix some bugs.

It adds the profile 'forge' to maven which is calling an ant script to build the required classes. The first run will take longer because Forge needs do download MCP, Minecraft, and all related resources as well as decompiling Minecraft and patching it with FML and Forge. That result is cached inside a zip file that is used on every further build to make the build process run faster. 

The ant script includes snakeyaml into the jar file. In order to avoid conflicts it is moved into the com.sk89q.worldedit.forge.yaml package.

This PR also adds a mcmod.info to the resources and jar file which is automatically filled with the up to date version specified in maven.

It fixes the player view direction and the printRaw command which was't printing the splited message but the hole message several times.

The reference to a world inside the implementation has been changed to a WeakReference to prevent WorldEdit from keeping unloaded worlds inside the memory.

This also adds an implementation of the regeneration code needed inside the ForgeWorld class and adds an better way of registration for command aliases and their usage to avoid empty help pages.

A working jenkins job can be found here: http://ci.thezorro266.com/job/WorldEdit/

If wanted, I can try to change the build process, so that it adds the forge classes to the main resulting jar but then we would need another solution for snakeyaml.

Comments and suggestions are welcome.