Added "Website Name" Option to svbtle options page

In the upstream version, the website link option allows you to add a link to a website on the wordpress sidebar. However, this link displays as the full URL, which for e.g. a LinkedIn or Facebook profile may be too long and unwieldy for a blog sidebar.

This change adds a field to the theme options for svbtle for Website Name, and uses that as the display name for the sidebar link.