histograms: add bin width input

* Adds bin width input.  (PR #386)
histograms: get value and apply bin size

* Gets value and apples bin size.  (closes #379) (PR #386)
histograms: rm scrolling as not needed

* Removes scrolling as it is not needed.  (PR #386)
histograms: file loading

* Loads other files and cleans up divs and rows.
  (closes #380)  (PR #386)
histograms: rendering on load

* Renders histograms no load.  (closes #382) (PR #386)
histograms: select/zoom for x axis

* Adds select/zoom for x axis.  (closes #387) (PR #386)
histograms: button styling clean up

* Cleans up the button styling.  (PR #386)
histograms: change in bin width drawing

* Changes how change in bin width is drawn.  (PR #386)