PKGBUILD suggestions

• Remove from depends gnutls, libnotify and libsoup.
  • libsoup removed upstream in GTK 3: continue & remove non-working code (amazon covers & audioscrobbler).
  • libnotify removed upstream in Migrate notification to GNotification.
  • Closes #1.
• Remove from makedepends perl-xml-parser and patch.
  • perl-xml-parser is a dependency of intltool and not used directly.
  • patch is a dependency of base-devel.
• Prevent libtool overlinking.