Add sprinting

When the 'sprint' key is held down, double the maximum speed. Split
the 'maxSpeed' option into walkMaxSpeed (default half) and runMaxSpeed.
Add sneaking

Move very slowly when crouching
Merge pull request #8 from deathcap/sprintsneak

Add sprinting and sneaking
update README
1.0.0
Update for gl-matrix voxel-physical

Requires deathcap/voxel-physical@217247c6f50284e89f22a2e5d5b60c38f35c6b32
Merge branch 'glm' - Update for gl-matrix voxel-physical

Conflicts:
	README.md
	index.js
Merge branch 'master' of github.com:deathcap/voxel-control