php-memcache: make it work with the new way of getting PHP backtraces
php: make phpstack more robust by using user_string_quoted()
php: add `phpstack_full()` to get a full backtrace with decoded args
php: display filename and line number in backtrace
php: fix display of int and booleans

`user_int()` should only be used for pointers on int, not for int in
userspace.