[Bug 1043] New: Errors in underlying IK solver are not correctly processed

http://bugs.orocos.org/show_bug.cgi?id=1043

Summary: Errors in underlying IK solver are not correctly
processed
Product: KDL
Version: kdl-trunk
Platform: All
OS/Version: All
Status: NEW
Severity: major
Priority: P3
Component: Kinematic Solvers
AssignedTo: orocos-dev [..] ...
ReportedBy: kiwi [dot] net [..] ...
Estimated Hours: 0.0

The chainiksolverpos_nr (and the _jl version) ignores any error in the
underlying IK velocity solver. With the correct set of input conditions, this
allows bad data to be returned.

While this patch fixes the problem, the solver tests now fail as they assume
that you can always invert any joint position. Obviously this is false, and
shows that the original implementation was incorrect in that the tests all
passed. See orocos-kdl/tests/solvertest.cpp:SolverTest::FkPosAndIkPosLocal(),
which uses random joint angles and always assumes success.