Per-manipulator ExtractIkParameterization

Added an overload to ExtractIkParameterization that can optionally filter by
robot and/or manipulator. These names are appended to the end of the group
name: "ikparam_values <iktype> [robot_name [manipulator_name]]".
Added GetIkConfigurationSpecification

This is a helper function on Robot::Manipulator that mirrors the functionality
of GetArmConfiguration. It constructs a ConfigurationSpecification that
includes an "ikparam_values" group (of a specified IkParameterizationType) for
the manipulator, referenced by robot and manipulator name.
fixed naming conventions
IkParameterization::GetConfigurationSpecification
Merge pull request #308 from personalrobotics/feature/IkParameterization

Added per-manipulator ikparam_value groups