Use desktop agent for LinkFragment

There seems to be an issue with 4.3 not handling redirects.
Revert "Use desktop agent for LinkFragment"

This reverts commit 9c7d796c3036eaa3460c0b7dfa3db1ac2254ae28.
Revert "Fix targetSdkVersion lint warning"

This reverts commit 1a2b39a8af340b8ed9ad286b4ba6f9d887ab110e.

Changing the targetSdkVersion to 18 causes the WebView client to show a
blank page when the browser is being redirected like on imgur.com.