zgui_ui_handler.py: port to last PyZio interface

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
zAttributeGUI.py: better name and documentation (and minor fix)

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
zGui: huge re-style review to comply Pyhton code style

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
ZioGuiHandler: skip interleaved channel on all channel view

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
ZioGuiHandler: fix minor graphical bugs/issue

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
ZioGuiHandler: comply with PyZio 0.4a, and remove useless import

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
GUI: use Plot object directly in the GUI

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>