At this time we cannot pass modifiers to those functions (SendMouseMoveEvent,
etc.).
In the wiki, it is marked as TODO:
http://code.google.com/p/cefpython/wiki/Browser#SendMouseClickEvent_(int_x_,_int
_y_,_int_mouseButtonType_,_bool
The patch attached fixes the problem, ensuring backwards-compatibility.