register chisel as proper tool

this allows the chisel to break blocks. Needs further cleanup of
setHarvestLevel("chisel", ...)
replace "chisel" with Chisel.toolclass where valid
finish tool functionality of chisel
Fixed the hardness of concrete

The hardness of concrete is now the same as stone and marble (hardness
2). Instead of being hardness 0.5
Concrete resistance fix

Now also changed the blast resistance of concrete to be the same as
stone, marble, etc.
Merge pull request #1 from Solestis/concrete-hardness-fix

Fixed the hardness and resistance of Concrete
fix issue with missing metadata in canHarvestBlock()

- new isCarvable() check for blocks missing metadata
- also add a generic havestLevel check instead of an obsidian-only check
Merge branch 'enable-leftclick'