Add wait() command to block on job completion

See kr/beanstalkd#203 for explanation
Detect _write() failures and return false

If we're gonna return false on errors, might as well check both
_write() and _read().

Mostly this was done because php generates a Notice on each write / read
call on a disconnected socket. 2 Notices per call was kinda annoying.
Add wait() command to block on job completion

See kr/beanstalkd#203 for explanation
Merge write-failure-detection into ifixit-production

Detect _write() failures and return false

If we're gonna return false on errors, might as well check both
_write() and _read().

Mostly this was done because php generates a Notice on each write / read
call on a disconnected socket. 2 Notices per call was kinda annoying.