fixes :

- fix build on windows platforms where getopt is not present : add a version of getopt called xgetopt (license ok) when called on Windows.
- fix parsing issues with Paje traces on Windows, caused by the switch to std::getline, and the fact that it now removes the endline character (the character after the end of an std::line is seen as a \n on linux, so the bug is not apparent but still present)

feature :
- add a window that allows the user to select the containers to display, reorder them or hide them (by drag and drop and checking/unchecking). The selected display can be saved to an xml file, and reloaded for another trace. Found in Preferences/Node Selection
- add the flag -c to specify such an xml file to load initially for a trace

known issues and todo :
- only works with OpenGl render : separate interface from work on the xml file to allow use with SVC
- zoom is badly handled, and containers are not redrawn with new sizes yet
- no tests done with non Paje traces, should work though
- lacks comments and cleaning
- put the window as a plugin ?