Merge phpdbg into PHP-5.6

diff --cc sapi/phpdbg/phpdbg.c
Simple merge

diff --cc sapi/phpdbg/phpdbg_frame.c
Simple merge

diff --cc sapi/phpdbg/phpdbg_list.c
Simple merge

diff --cc sapi/phpdbg/phpdbg_prompt.c
Simple merge

diff --cc sapi/phpdbg/phpdbg_utils.h
Simple merge