user/jszakmeister: add a patched version of indent/html.vim

This version comes from https://bitbucket.org/audriusk/dotvim, where it
has been patched to line up multi-line tags with the start of the
attribute, rather than the start of the tag.  For example:
    <img src="..."
         alt="...">
user/jszakmeister: add a visual mapping to yank to the clipboard.
Add a few more active file types to Syntastic.
jszakmeister: setup xdg-open as the default url browser

This helps in environments that are not KDE or Gnome, such as Unity.