Add pages to show information about a particular flowcell.

-- in both human and RDFa formats.

Also I implemented get_absolute_url for flowcells & lanes, which
means "view on site" pops up on the flowcell admin page.

Also with modifying the templates for RDFa, many more elements
on the library, flowcell, and flowcell lane detail pages link to
each other.

I moved the table formatting css out of the library page
and into app.css.

I also switched experiments/views.py from using Context to RequestContext
which provides the default media url to the template.

There were a few changes to samples/views.py to get the more informative
object to the template instead of our on-the-fly created lists.