First stab at fixing gh-4.
Per issue gh-11, make R scripts input and output direcories script
parameters, and change their locations to be under the rails /tmp
directory.
Added code to add xml tags giving the latitude and longitude of each site to the XML document in multisite_config.xml.
Added code to add latitude and longitude information to each biome group in ghgvcR_input.
Fixes for issue gh-15:

Show/Hide the "Add Additional Location" button according to whether or
not the user has selected coordinates for the currently active
location.

Prevent adding an additional location when the user hasn't checked any
ecosystems for the active location and warn the user.

Add some minimal instructions for using the calculator and revise and
clarify existing text.
In create_config_input, when creating multisite_config.xml, make lat
and lng of site element into attributes instead of making them child
elements (c.f. gh-18).

Added new 'get_svg' method for changes related to gh-7.
Added route for the get_svg action of the workflows controller (c.f. gh-7).
Changed the calculate button's click function so that it inserts the
contents of /tmp/out/output.svg into the highcharts_container element
if that file exists and only falls back out the highcharts-generated
svg images if it does not exist.  This supports changes related to
gh-7.
In get_svg, eliminate type designation in send_file to play nicely with jQuery.html method.
Changed download_csv to send the R-produced output.csv file in the
rails /tmp/out directory, fixing gh-23.
Per gh-4, added checkboxes for switchgrass.
Merge branch 'work-for-1-10-14'