Add webhelper extension and support for loading extensions

New phpdbg commands:
dl [path] - loads module / Zend extension
wait - waits for incoming connection from a phpdbg_webhelper module

Webhelper module is a UNIX domain socket to which a SAPI with the phpdbg_webhelper module loaded will write to the socket information about its whole environment.
phpdbg can then run the request locally [TODO: write the request back to the sender]
Fix segfaults, reorder files and set filename to exec
Do not unload phpdbg module in any case
Send a \x03 during execution to interrupt (POSIX only)
Made some functions async safe and provide interactive shell in signal handler
Fixes also (as a side-effect) a possible bug in list function when included files become unreachable after loading by caching the file contents
This is already pretty stable; a (restricted) ev and sh may follow.
Added support for a restricted ev (variables only) in async safe contexts
Use or instead of and for libedit and readline
LIBREADLINE => HAVE_LIBREADLINE
Add transfer of output back to webserver and merge master in

Conflicts:
	config.m4
	phpdbg.c
	phpdbg.h
	phpdbg_cmd.c
	phpdbg_prompt.c
Fix issues with path names and cwd
Fix (system) ini entry transfer
Disable automatic resetting of imported auto_globals
Fix infinite recursion issues (segfaults)
Use PHP 5.4 compatible zend_execute in #if
Merge branch 'webdata_transfer'
Merge branch 'master' into xml-protocol

Conflicts:
	phpdbg.c
	phpdbg.h
	phpdbg_cmd.c
	phpdbg_cmd.h
	phpdbg_frame.c
	phpdbg_info.c
	phpdbg_list.c
	phpdbg_print.c
	phpdbg_prompt.c
	phpdbg_utils.c
	phpdbg_utils.h
	phpdbg_watch.c