R=rsc http://codereview.appspot.com/6210059

R=rsc http://codereview.appspot.com/6197057

R=rsc http://codereview.appspot.com/6201049

R=rsc http://codereview.appspot.com/6128063

R=rsc, rsc http://codereview.appspot.com/6097047

R=rsc http://codereview.appspot.com/5989059

R=rsc http://codereview.appspot.com/5988058

R=rsc http://codereview.appspot.com/5970072

R=rsc http://codereview.appspot.com/5847060

R=rsc http://codereview.appspot.com/5900076

R=rsc CC=plan9port.codebot http://codereview.appspot.com/5748043

there is no more blank image when toggling fullscreen, when unminimizing, or at startup; this also means that we can live resize, but we only enable live resizing with Page, because it seems useless for other apps, and Acme and Sam bug with it. The tradeoff is that bottom corners are sometimes automatically rounded. There is a way to prevent the rounding here: http://parmanoir.com/Custom_NSThemeFrame but this would obfuscate the code. Instead, we make sure that the corners are always rounded. Closing the window while its content is updated causes an exception, without this patch. This seems to happen regularly with stats(1). This patch avoids a possible deadlock at startup, which I never experienced. If I recollect right, there is little chance that this happens on a multi-core CPU. Minimizing now activates next app in line, and Devdraw now stops drawing while minimized. R=rsc CC=plan9port.codebot http://codereview.appspot.com/5499043

R=rsc CC=plan9port.codebot http://codereview.appspot.com/5745043

R=rsc CC=plan9port.codebot http://codereview.appspot.com/5749043