Expose output json option via CLI - refactoring.

This output file contains a fairly detailed breakdown of test results including stuff like command line, standard outputs, standard error, exit code, job metrics, etc....
Merge XUnit information into structured data (json) output.

XUnit information contains information about whether a test actually passed or failed - as well well as more detailed log of failure - merging this into the structured JSON blob allows one to easily combine these two sources of data - and say build a test report HTML page.
Rework code so new GalaxyTestResults doesn't require summary to execute.

This way full structured JSON with XUnit information is merged in is written regardless of whether summary is disabled.
Small language modification.
Prettier, more structured HTML reports for tests.

This version of the HTML report includes information pulled out in a structured way such command-line, job standard error and standard output, failure reasons, etc... and has a much more modern look and feel thanks to bootstrap.

Basically - this replaces the HTML report generated by Galaxy with one generated here in planemo using the structured data json stuff. It generates a single static HTML page with jquery and bootstrap embedded directly in the page as well as custom JavaScript code for parsing and displaying the structured data JSON.

Before and after screenshots at http://imgur.com/a/TZYJq.
Merge pull request #38 from galaxyproject/prettier_reports

Prettier, more structured HTML reports for tests.