fix loading Chunks that have not populated completely
fix loading Chunks that have not populated completely

Minecraft is upgrading/generating Chunks now with much more differnt stages than before. Several data tags are not present in early stages. Minutor was crashing when loading such Chunks.

this fixes #143 and some other possible issues

mrkite/minutor,EtlamGit/minutor,mrkite/minutor,EtlamGit/minutor,mrkite/minutor,EtlamGit/minutor,EtlamGit/minutor,mrkite/minutor,mrkite/minutor,EtlamGit/minutor