installed underscore with bower
added underscore to app js
average sales per hour per day are computed, and the sample size n is displayed in the tooltip
Merge branch 'feature/hourly_sales_report' into develop
made date_selector partial
reports controller inits with a @urls array and @default_lavu_params hash.  the report action method can call the set_dates method, which will parse the start_date and end_date params, and add them to the @default_lavu_params hash.  build_url is called, which accepts the report id number and then a hash of additional url params you want to send to lavu
both existing reports use the date_selector
parser to get the web link from download link updated to match new code
Merge branch 'feature/report_date_selection' into develop