[PATCH] Output control

Current output control code have some problems. This patch solves some. 1) ob_end_clean/ob_end_flush destory buffer that is not supposed to. Deleteting output compression does not make sense once output is started. (Additional checks) 2) Memory leak, crash when deleting output buffer when nesting level is 0. (Additional checks) 3) User has no way to know which buffer is deleted by ob_end_*() functions. (ob_get_status()) 4) User has no way to know buffer functions are executed correctly or not. (ob_*() functions return bool) 5) User has no way to know status of buffers. (ob_get_status()) TODO for output control. - Implicit flush is not working. Need more work to make implicit flush actually work with nested buffers... - Fix crash with user defined (PHP script) output handler. Any comment is appreciated :) PS: Session patch, I've posted here, is also includeed in this patch. It fixes verious session problems. -- Yasuo Ohgaki