Also
- simplify and add tests
- remove large memory leak (persistant store of all non-project layers)
- remove broken support for direct loading postgres/virtual layers
by string (Python version was very broken and would never match
a postgres/virtual layer)
This algorithm allows you to extract specific nodes from geometries.
Eg you can extract the first or last node in the geometry.
The algorithm accepts a comma separated list of node indices to
extract, eg 0 = first node, 1 = second node, etc. Negative indices
can be used to extract nodes from the end of the geometry. Eg
-1 = last node, -2 = second last node.
