Fixes #606
Check if the tag is found.
Fixed bad variable.
Fixed at least a little of the plugin guide.
Fixed some more.
Added cChunkDest::UpdateHeightmap()

This function is necessary for plugins manipulating the generated chunks, they need to update the heightmap before it is passed back to the generator.
Added cPluginManager:BindCommand() form to the API.

That's the canonical way to call static functions.
Fixed cLineBlockTracer:Trace() signature.
Wolf: If Owner tag is missing a normal ownerless wolf will spawn.
Inversed condition.
Merge pull request #607 from mc-server/Wolf_Owner_Saving

Wolf: Their owner now gets saved.