When user hover the Xref string of a terminal, the string color change
to blue to advise user the xref is clickable. Double click on the blue
Xref go the folio of the terminal and zoom the view to the terminal.
TerminalStripLayoutPattern class is now a shared pointer between all
terminal strip item.
QETProject have now a new class : ProjectPropertiesHandler
the goal of this class is to manage every kind of properties used in the
project, this class will be strongly used in future.
