changed canvas widget to grid widget.

Ignore-this: a6b41fc769bd8ebbc4a449af78d4a321

also the grid widget does not get placed automatically and acts
like other widgets where you have to explicitly place it.

this breaks any app that used the canvas.

also added ability to change the height or grow the height of the app

darcs-hash:20131122143921-c21fe-60a130132f72b481e66481d519ad92c171310ffe
udp tweaks

Ignore-this: 1c893f8d6c493f15a54238040e3aa8ff

used more fine grain locking because a really large message could stop the pipeline.

darcs-hash:20131122144117-c21fe-07268dccfcebe96c73f8c1cd49c6d6466534aeec
updated udp tick threshold to be lower

Ignore-this: 9dc1db392cd8f16143aa0888c3d0726

darcs-hash:20131122145110-c21fe-f94a5b8f3df3fed0528865d6b324e02a7bbd98d8