[Patch]Add support for custom values, dimensions and metrics

Take a look at this patch: https://pastebin.com/QDTsAvmk

I have made a few changes to allow custom values, dimensions and metrics. There is an option to compute the values for those settings using javascript. This can be customized per page/post. They don’t have a disable button because empty fields are ignored.

options.php has been moved to admin/options.php. Some textareas are greyed out when disabled. There are other minor changes as well.

I think screenshots should be moved to the svn directory named assets in order to reduce the size of the plugin. They should still be displayed in the plugin page here in www.ads-software.com.

There is a new google analytics built-in option to autodetect the domain. If you want it to be used by default in new installs change NKgoogleanalytics.php line 167 to:
add_option('nkweb_Domain_Auto', 'true');

In my opinion deleting all saved options during plugin deactivation is too extreme. I would expect to have my options deleted only if the plugin is uninstalled. If you agree with me change NKgoogleanalytics.php line 185 to:
function uninstall_NKgoogleanalytics()

And line 482 to:
register_uninstall_hook(__FILE__, 'uninstall_NKgoogleanalytics');

https://www.ads-software.com/plugins/nk-google-analytics/