On HiDPI displays, the color boxes of timed events
appear distorted and not squared.
Fix that by setting a fixed size, and changing the
box alignment to always shrink to a squared state.
The current GcalEventWidget implementation is a direct
GtkWidget subclass, which means we have to take care of
all the implementation details such as raising GdkWindows
and managing the drawing all by ourselves.
The event widget, however, can be easily described through
a GtkBuilder file. This would simplify the implementation
and makes us maintain less code.
Fix that by making GcalEventWidget a GtkBin subclass.
Georges Basile Stavracas Neto