ENH: Inital commit

This module is a new version of PathPlanner.
In the future, VisuaLine will be merged.
ENH: Modified reslicing GUI

Note: Code need to be cleaned
Issue with ruler intersection (intersection is shown in all viewers)
STYLE: Cleaned source code
BUG: Fix a crash

INFO: GetPositionWorldCoordinates is expecting a double array
with 4 values, not 3.
ENH: Modified GUI

BUG: Fixed an issue, reslicing automatically when changing trajectory
STYLE: Modified GUI

PushButtons colors and style
BUG: Fix a crash when getting fiducial coordinates
COMP: Fixed code to match with changed in vtkMRMLSelectionNode API.
BUG: Do not reslice when changing trajectory

STYLE: Cleaned code
STYLE: Fixed extension information
STYLE: Renamed PathXplorer to PathExplorer