implement connect timeout parameter

[glensc]

when accepted, please tag 2.3.2 release

[glensc]

before:

# time php -r 'require "rdb/rdb.php"; print_r($c=array("timeout"=>1,"host"=>"timeout.google.com")); $r = r\connect($c);'
Array
(
    [timeout] => 1
    [host] => timeout.google.com
)
PHP Warning:  stream_socket_client(): unable to connect to tcp://timeout.google.com:28015 (Connection timed out) in /usr/share/php/rdb/Connection.php on line 455
PHP Stack trace:
PHP   1. {main}() Command line code:0
PHP   2. r\connect() Command line code:1
PHP   3. r\Connection->__construct() /usr/share/php/rdb/global.php:87
PHP   4. r\Connection->connect() /usr/share/php/rdb/Connection.php:118
PHP   5. stream_socket_client() /usr/share/php/rdb/Connection.php:455
PHP Fatal error:  Uncaught RqlDriverError:
  Unable to connect: Connection timed out

  thrown in /usr/share/php/rdb/Connection.php on line 459

real    0m9.094s
user    0m0.047s
sys     0m0.007s

[glensc]

after:

➔ time php -r 'require "rdb/rdb.php"; print_r($c=array("timeout"=>1,"host"=>"github.com","connectTimeout"=>1)); $r = r\connect($c);'
Array
(
    [timeout] => 1
    [host] => github.com
    [connectTimeout] => 1
)

Warning: stream_socket_client(): unable to connect to tcp://github.com:28015 (Operation timed out) in /Users/glen/scm/php-rql/rdb/Connection.php on line 476

Fatal error: Uncaught RqlDriverError:
  Unable to connect: Operation timed out

  thrown in /Users/glen/scm/php-rql/rdb/Connection.php on line 480

real	0m1.119s
user	0m0.056s
sys	0m0.034s