Axis Context Menu

Adds a uicontextmenu to x and/or y axis of an axes. The regular axes uicontextmenu stays intact.

uiaxiscontextmenu adds special contextmenu to X & Y axis of an axes.

uiaxiscontextmenu() adds two properties to an axes (gca in default):
"XUIContextMenu" and "YUIContextMenu".
After this, these properties can be set to a regular uicontextmenu that
will be shown when the mouse is on one of the axis and right clicked.

uiaxiscontextmenu('remove') removes the axis contextmenu from gca.
uiaxiscontextmenu(hAxes, ...)is the same but for the explicitly axes
"hAxes". hAxes can be scalar or vector of axes numeric handles.