add test for integer values in options array

Hi,

I was using BootForm::select and I was trying to create integer values for the options. I found that if I started my array with '1' the select worked perfectly, but if i started with '0' then it didn't... i think this is because arrays erase the "type" of the key if it equals an integer value

$array = array();
  $array['1'] = 'value';
  var_dump($array);
array(1) { [1]=> string(5) "value" }

my options array looked like this
working ... array('1' => 'Active', '0' => 'Inactive')
broken ... array('0' => 'Inactive', '1' => 'Active')

I am unsure of how to fix the issue, but i thought i would send along a pull with a test to show what i found.

BootForms has been great,
thanks for putting it together!