flexible waypoints handling for the MJT UR client

• updated reference API (SDK 1.9.0).
• GUI rewritten from scratch with Swing.
• the package now provides the MJTrajectory and MJWaypoint program nodes, allowing a way more flexible management of waypoints.
• the service interface is now based on the XMLRPC protocol. there are three different channels of communication:
  • between the URCap (Java client) and the service provider for trajectories generation and retrival.
  • between the URCap (Java client) and the daemon service proxy (Python server) for loading trajectories into memory.
  • between the robot program (URScript client) and the daemon service proxy (Python server) for trajectory following.
• trajectories are defined in terms of polynomials that are evaluated by the daemon proxy service.
• the trajectory following control logic is handled by the proxy.
• the proxy also implement a mock for the service provider for local testing, in particular it includes:
  • mock for the trajectory_generate service (required by the Java client).
  • a rest-to-rest trajectory planner between successive waypoints, based on (standard) double normalized quintic polynomials.
  • the mock is enabled whenever the service provider hostname is set to "localhost" on the installation node.
• the URScript generation is now parametric and the source code of both the installation and trajectory program nodes are stored as part of the package resources.
• default values for installation and program nodes are now defined using a Java properties file, stored as part of the package resources. the properties file is also shared with the daemon service proxy.
• using fancy input data validation on node input fields (many, many thanks to Apache commons validator).