Assign php token constants based on actual lexer token values

Omit the values from constants.idl.json, and provide them
via hphp.tab.hpp.

Differential Revision: D957423
Delete unused hphpc list assignment code

Differential Revision: D959103
Fix stream_socket_recvfrom & stream_socket_sendto

IPv6 addresses for stream_socket methods in PHP must be bracket
enclosed.

Differential Revision: D958537
libmemcached support for all 0.4x+ versions

It turns out the Ubuntu 12.04 image I thought was using 1.0.16
was using 0.44 and OSX was using 1.0.17. This should fix compilation on
libmemcached 1.0.8 - 1.0.16.

Closes #1022

Differential Revision: D957901
Make test/run's finding repo compiler more robust

Use hhvm --hphp instead of hphp to find the repo compiler as it
is more portable

Differential Revision: D959508
Test updating Travis script to -x
Merge branch 'master' of https://github.com/scannell/hiphop-php