Add question to reset execution in run/exec/clean
disable output buffering by default
remove dodgy param parser, bring userland breakpoint api inline with PHP7
Fix nullptr dereference in clean without exec context
Stabilize execution, always run destructors and extended file breakpoints
Fix last commit, and do not output unnecessary information
Do not execute anything after quit or clean command
Merge remote-tracking branch 'origin/PHP-5.6'

Conflicts:
	sapi/phpdbg/phpdbg.c
	sapi/phpdbg/phpdbg_bp.c
	sapi/phpdbg/phpdbg_list.c
	sapi/phpdbg/phpdbg_parser.c
	sapi/phpdbg/phpdbg_parser.h
	sapi/phpdbg/phpdbg_prompt.c