Updated for 0.7

Can now use a plow to remove unwanted voxels

Big updates & fixes:

-- All code updated with Mirzipan's latest Re:Core definition structure; all tools work in Survival again
-- All tools now have proper animations when being used
-- All voxels now have footstep sounds when you walk/run on them. Gravel even has dust.

Upped durability of rock hammer and trowel from 10 to 20 hits.

Now Lavender and Old Grass can be plowable like other soft-ground voxels.

When used up, gravel bag now returns your linen string to you.

Also, gravel can now be placed on top of gravel to fill in "dead" spots.