Update EDD License routines

[danieliser]

Newest EDD sample plugin uses this after the request is made. It includes more elaborated status messages, as well as a non 200 response handler.

		// make sure the response came back okay
	if ( is_wp_error( $response ) || 200 !== wp_remote_retrieve_response_code( $response ) ) {

		if ( is_wp_error( $response ) ) {
			$message = $response->get_error_message();
		} else {
			$message = __( 'An error occurred, please try again.' );
		}
	} else {

		$license_data = json_decode( wp_remote_retrieve_body( $response ) );

		if ( false === $license_data->success ) {

			switch ( $license_data->error ) {

				case 'expired':
					$message = sprintf(
						/* translators: the license key expiration date */
						__( 'Your license key expired on %s.', 'edd-sample-plugin' ),
						date_i18n( get_option( 'date_format' ), strtotime( $license_data->expires, current_time( 'timestamp' ) ) )
					);
					break;

				case 'disabled':
				case 'revoked':
					$message = __( 'Your license key has been disabled.', 'edd-sample-plugin' );
					break;

				case 'missing':
					$message = __( 'Invalid license.', 'edd-sample-plugin' );
					break;

				case 'invalid':
				case 'site_inactive':
					$message = __( 'Your license is not active for this URL.', 'edd-sample-plugin' );
					break;

				case 'item_name_mismatch':
					/* translators: the plugin name */
					$message = sprintf( __( 'This appears to be an invalid license key for %s.', 'edd-sample-plugin' ), EDD_SAMPLE_ITEM_NAME );
					break;

				case 'no_activations_left':
					$message = __( 'Your license key has reached its activation limit.', 'edd-sample-plugin' );
					break;

				default:
					$message = __( 'An error occurred, please try again.', 'edd-sample-plugin' );
					break;
			}
		}
	}