tidy up admin settings

I have tidied up the the admin settings pages

Since the default action when people click on the plugin in admin menu is to go to settings tab, I put the main metatable editing code under settings.
I also created you a new tab called "Edit meta" which you can find in hseo.php file. I put the content in that and also metatable using templates so you can easily edit it from now on

I checked the saving of metatable data and it is saving fine, but the tab seems to change to Overview after saving. This is a jquery error in Hotaru which I am working on now for v.1.5.0 release. It is one of the small things holding up the release at the moment

Let me know if you need any more assistance along the way