JSON ERROR: The decoded property name is invalid

[robmyers82]

We are receiving a 'JSON ERROR: The decoded property name is invalid' error message when trying to retrieve orders. We discovered why this is caused: there is a plugin installed in the store's WC that is adding the Unicode NULL character (\u0000) to a metadata property name. This issue can be resolved by stripping out any instances of the null character in the response body before decoding JSON at https://github.com/woocommerce/wc-api-php/blob/master/src/WooCommerce/HttpClient/HttpClient.php#L372:

$body = str_replace('\u0000', '', $body);

[robmyers82]

Please note, I submitted a Pull Request to resolve this issue at #257. However, it looks like it may have some issues with validation that appear to be resolved with another Pull Request.