client js: use iframe onload event to detect when iframe changes, allows
setting banner even for non-html captures, instead of frame notifying parent
will fix issue mentioned in #41
move script from frame_insert.html -> wb_frame.js
banner: remove client side 'capture_str' formatting, just output wbinfo.timestamp,
allow js to format as needed, also helps with #41
update tests to only look at timestamp
rewrite: better parametrize live rewrite timestamp cookie, restore LiveResourceException
Merge branch 'develop' into https-proxy