mcpi-e 0.3.0 release

1. Enhancement for using mcpi in server with multiple users
   User could pass player username as 3rd parameter when create a new Minecraft api instense.

ex: mc=Minecraft.create(address,port,name)

Change mc.Player to use entity so it will not pick the first user in the server.

2. Limit the Usage of mcpi
   Add the _send command 0.05s interval to slow down the speed
   limit the useage of setBlocks/setBlock
   limit the setBlocks W+H+L < 300 and WHL <1000
   max abs(y) of the setBlocks/setBlock will be 256