Specs: Split apis.md into dom.md, events.md, idl.md, and move the remainder into README.md and modu…

sky/specs/runloop.md

+Sky's Run Loop
+==============
+
+Sky's run loop consists of running the following, at 120Hz (each loop
+takes 8.333ms):
+
+1. Send scroll and resize events if necessary, limiting each handler
+   to 1ms, and limiting the total time spent on these handlers to 1ms.
+
+2. Update as much of layout as possible; after 1ms, stop, leaving the
+   remaining nodes unprepared.
+
+3. Update as much of paint as possible; after 1ms, stop, leaving the
+   remaining nodes unprepared.
+
+4. Send frame to GPU.
+
+5. Run pending tasks until the 8.333ms expires. Each task may only run
+   for at most 1ms, after 1ms they get a (catchable) EDeadlineExceeded
+   exception. While there are no pending tasks, sleep.
+
+TODO(ianh): Update the timings above to have some relationship to
+reality.