Update dependent code accordingly.

Check if all ports in light input data a real input ports of the node to
be analyzed. Otherwise data might be silently discarded. This should not
happen if the nodes are properly connected...

Update examples & tests accordingly.

Add name parameter to IdealFIlter::new

Fixed missing inverted() fn.

code cleanup

Various code cleanups.

Add corresponding unit test.
Closes #66

Use OpmResult defined in error module.

Add general OpmResult typedef to error module.

Further code cleanup

code cleanup