Improved furnaces

* Fixed progress bar on 1.8
* Fixed bugs
* Improved code
* Fixes #1068
* Fixes #1070
Fixed a number of stylistic issues.
Nullptr?
Simpler code.
Furnaces now update their block entity type

Therefore improving cChunk's variable boundary checking.
Fixed failure for cRankManager to restart
Merge pull request #1502 from mc-server/furnaces

Improved furnaces