REST services to serve JBrowse

The monarch API ought to serve up genomic features with annotations attached for display in JBrowse (or even in a div in our own app).

See http://gmod.org/wiki/JBrowse_Configuration_Guide#Writing_JBrowse-compatible_Web_Services

We will initially test this to serve up a gene model, and variations to be drawn on it, including marking up phenotype.