remove debug code
fix #440
Static cache abort should output the captured buffer.
disable the cache if captcha shown

Original code aborted the HTML cache, but this really should be treated
the same as when we have an image processor uri--the caching of the page
gets disabled and then normal cleanup takes care of things.
add some debug code for not-found images
Merge remote-tracking branch 'origin/1.4.5' into 1.4.6