Add deepseq to dependency list.
Add cabal exports. Clean up Data.QuadTree.Grid
Data.QuadTree.Grid:
-> Remove ineffective UNPACKs.
-> Remove size attribute from Leaf data constructor. It can always be derived from the Scale and whether or not we have a Just or Nothing.
Remove bangs. Implement unsafeSet.
-> The bangs may be added in the future, but they may not be worthwhile without UNPACK. This must be tested later.
-> The current implementation should work, however, it is untested. Additionally, it may be too slow.