Support php5.3

Hi,

PHP5.3 still use some production environment. adding 5.3 support is not bad thing i think.
Could you review and merge this pull request?

this pull request includes 2 fixes.

5.3 support:
* use `zend_hash_copy` instead of `object_properties_init`.
* check PHP_JSON_PRETTY_PRINT constant (5.3 doesn't have it)

windows fix:
* add missing dependencies (json, session)

Thanks,