Move ST_TriangleContouring, as a table function
Fix wrong iso applying on Countouring
Add code coverage plugin
More coverage
Add unit test contouring
coverage of 79 percents
Prevent calculation from being done 3 times

H2 calls this function 3 times, sometimes just to get the column names.
This is a hack to prevent the calculation from being done 3 times. It is
done only when necessary. See
    https://groups.google.com/forum/#!topic/h2-database/NHH0rDeU258
Merge pull request #228 from agouge/perf

Prevent calculation from being done 3 times
H2 calls this function 3 times, sometimes just to get the column names.
This is a hack to prevent the calculation from being done 3 times. It is
done only when necessary. See
https://groups.google.com/forum/#!topic/h2-database/NHH0rDeU258
Merge remote-tracking branch 'irstv/master' into triangle_contouring

Conflicts:
	h2spatial-ext/src/main/java/org/h2gis/h2spatialext/CreateSpatialExtension.java
Fix merge imports
Add remarks on function
Fix unit test
Fix ST_TriangleContouring
Move internal class
Fix javadoc
Merge pull request #229 from nicolas-f/triangle_contouring

Add ST_TriangleContouring
Add missing 'w' parameter
Add first attempt at ST_ShortestPath
Correct ST_ShortestPath and add a unit test
Add edge geometries to the output of ST_ShortestPath

TODO: Recover the spatial field index correctly