Slight change to category processing

Thanks for this plugin! I came across one issue while testing.

The code that checks whether or not a category is an integer works if the input is JSON. It does not work with form data as everything comes through as a string and is_int checks variable type.

I changed this line:

if(!is_int($data['x-categories'][$x])) {

to this:

if (!ctype_digit($data['x-categories'][$x])) {

and the category code now works correctly for me.

https://www.ads-software.com/plugins/json-rest-api-wp-api-categories-and-tags/