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
Use full duplex stdin/stdout socket
First draft of an xml protocol
A few general segfault fixes
Fix breakpoints and listing
Add notification at script end
Add info globals command
Merge branch 'master' into xml-protocol

Conflicts:
	phpdbg_prompt.c
Use consistently "num" for an nth opline number
Fix accidental short-circuiting when comparing fds (& warnings)
Use more consistent naming in info command for xml protocol
Better naming in list command and inform about filename
Always add a newline before a warning or a notice
Fix test after adding script ended notice
Merge branch 'master' into xml-protocol

Conflicts:
	phpdbg_utils.c
Fix tests
Make print command xml output more consistent
Make phpdbg_prompt.c xml messages more consistent