Implement Array.prototype.every. Fixes gh-282

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>
Changing this to `if not callbackfn(t, this[index], index, this) then` checks for falsy semantics, allowing this to pass on Node and Colony:

```
// Stops when "falsy"
var count = 0;
[1, 2, 3].every(function(value, index, object) {
  count++;
  return '';
});
result += count;
```