Add h2topology pom
Add h2spatial-api dependency
Add starting point for ST_Graph
Record nodes table. TODO: Remove duplicates

Duplicates should be removed using an RTree or something similar.
Use a quadtree to avoid duplicate nodes

TODO: Add edges
Create edges table as well
Remove unneeded dependencies

We'll need them later though
Do a little simplification
Make sure quadtree query intersects envelope

Sometimes the point(s) returned by the quadtree query does not interect
the point of interest. Now we cover this possibility.
Change the constraint function for geometry domains
Simplify further by using global variables
Shape file driver now expose Geometry type constraint
Change javadoc of ST_ExteriorRing
Add tolerance

Note that only the first and last coordinates of linestrings may be
snapped together. So in the test, (7 5) is snapped to (7.1 5), but
(4.05 4.1) is not snapped to (4 4).
Introduce orient by slope + test
I should have put the default tolerance
Make hard-coding of names explicit
Make sure geom!=null
Add better tests
Verify geometry type and clean up appropriately

Make sure each geom is of type LINESTRING or MULTILINESTRING and fail if
not; delete the nodes and edges table in this case.