And overhaul resize and paint events to fix layout edge cases in
which Calendar wasn't filling its parent widget completely. Ensures
month views always display prior month days for click navigation.
Converts Calendar app layout to GML.
Now that WindowServer broadcasts the system theme using an anonymous
file, we need clients to pledge "recvfd" so they can receive it.
Some programs keep the "shared_buffer" pledge since it's still used for
a handful of things.
