Don't run travis against master (phpng)
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