Move block texture and hardness definitions to use voxel-registry
Disable/enable voxel-fly plugin in survival/creative mode

Requires https://github.com/deathcap/voxel-fly/commit/3a57780cfc1fc79ba8877542c67eadb4dbc313a3
Cleanup and refactor
Use ever module to listen for DOM events
Make dirt harder
Load voxel-registry as a plugin, and materials dynamically. Requires https://github.com/deathcap/voxel-engine/commit/c674690599d24099dc85b7f8580430650b4a092a
Add voxel-plugins-ui, dat.gui for enabling/disabling plugins
Merge master
Regenerate bundle.js