Make sure the 'href' attribute of the base tag points to the web page's base..

[WetHat]

Fixes issue #201 .

Some website specify the href of the base tag as '/' rather than the base uri of the website. This causes the JDOMParser to set:

• dom.baseURI = 'chrome-extension://nghfdnngoejlhedogdpikdlkmdfoojii/'
• dom.documentURI = 'chrome-extension://nghfdnngoejlhedogdpikdlkmdfoojii/_generated_background_page.html'

when it parse HTML text in the background context. As a consequence Readability.js generates garbage for local links.

With this change https://steven-giesel.com/blogPost/79ce95ad-17a9-4537-8f1b-48d71efc585d reported by @nicolaiarocci works ok;