Points added to multiple waterbodies due to error margins

[oehm-smith]

Commit 5.3.20 - On Lake Burley Griffin, there is one point to the east of lake that is included in 2
pie graphs. That seems to be because the point itself is in LBG but one error margin point is in a different waterbody (that looks like a hole in the LBG polygon).

The algorithm to fix needs to be along the line of "if source point is in a water body then don't use error margin points to test if in waterbody".

[oehm-smith]

I'm deferring work on this and may never actually do. The work log entry i added to __ says:

• This is a tough problem and I don't know it is worth the effort
• The problem is in calculateLayerIntersections(). The intersection
  is all points (source and errorMargin). But the uses of an EMP and SP
  spans across polygons (by definition of this problem - if in the same
  polygon GisOps.filterSourcePoints leaves only SPs). So the filtering
  needs to be moved to be across polygons. AND the order might be different

• the EMP could be added first or the SP could be added first