refactored views
Moved reset link into update form

* Not semantic, but aligns them on the same line
Removed dead code

* "print_and_flush" was for debugging, and was not being used
Declared public/private methods in Histogram

* update_histogram is public, called form HistogramsController
  for updates
* Everything else should be private
  * the #crunch private method is tested in the Histogram spec
    despite it being private; its functionality seems complex
    enough to warrant testing
* Also refactored photo_url method
Refactored Histogram model