Material values: hardness, blast-resistance, etc.

This PR fixes #384 and is an alternative for #385.

**What's WIP:**
The code is 100% finished and ready for review, only the concrete values must be filled in. I'll start on doing this, when it's said that the code is correct.

For testing: torches drop items now, since they have hardness == 0 and insta-break therefore.

If explosions/tnt are pulled before this, I'll add also correct blast-resistance values for explosions to this PR, otherwise I'll add them to the tnt-PR.

This PR should be easily extendable for other values as well (f.e. light-level). It could also replace hardcoded values if wanted (f.e. whether blocks can absord). If there's the need, a Glowkit-PR could be created, allowing plugins to fetch these values as well.