Enhance coverage simplification to handle one tolerance per geometry

[nstrahl]

An enhancement has been made to the coverage simplification algorithm (simplify and simplifyInner). Currently, coverage simplification only allows one global tolerance value to be specified for the entire coverage. The proposed enhancement allows multiple tolerances to be passed in as a list, where each entry corresponds to a geometry. The geometries can thus be simplified with different tolerances while still ensuring topological correctness. At coinciding coverage edges the lowest available value is utilized.

This will be very useful for solving problems related to the boundary discretization of tessellated geometries.

The following figure shows an example where the boundary polygon is simplified with a tolerance of 1, and the other hole polygons with 1 and 0.5.

Here is another one with tolerances of 50 and 10.

[dr-jts]

Conversion from a string to an array of tolerances should be left up to client code, since it's highly usage-specific. It can be done in CoverageFunctions as well, to allow for easier testing and experimentation.

[nstrahl]

Ok, then I will be moving that method into the JTS test builder code

[dr-jts]

The class Javadoc needs some mention of the semantics when using tolerance-per-geometry. Specifically, there should be a comment like:

The simplifier allows specifying the simplification tolerance separately for each input geometry.  Shared edges are simplified using the lowest of the tolerances for the adjacent geometries (i.e. the least amount of simplification is performed). This allows specific geometries in a coverage to be simplified less than other geometries (or to force their boundary to be preserved without simplification).