add genome rendered images to Gene page

[nathandunn]

Going to use the visualization server to generate images on the gene page initially. This will let us know what data is still missing or other potential issues.

http://dev.alliancegenome.org:8891/?url=http%3A%2F%2Fbw.scottcain.net%2Fjbrowse%2F%3Fdata%3Ddata%252FCaenorhabditis%2520elegans%26loc%3DIV%253A12893065..12894996%26tracks%3DAll%2520Genes%26highlight%3D%26screenshot%3Dp20o0r0n0u0b1m111s000000z1~0h2500i0q0d0&format=PNG&delay=16000&width=600&height=300&zoom=1&quality=0.7

[nathandunn]

• need chromosome, species, symbol, fmin / fmax

  • default fmin /fmax = 0/100
  • attempt with just symbol

• remove track labels tracklabels=0 (update jbrowse version)?

• need to get passed in or most recent assembly

[nathandunn]

Works using these in conjunction with these branches:

• https://github.com/nathandunn/jbrowse/tree/export_json
• add fmin / fmax to genomeLocation #249
• fix iframe height or render using image in PhantomJS

Working on it here: https://github.com/nathandunn/agr/tree/test_jbrowse_tempfix