menubar (#804)

* menubar 1

* zoom switching

* centering, pixel perfect canvas

* remove dead args and code

* clipping

* remove log

* if

* connect props

* lint

* undo

* logo left, componetize

* graph back to full height

* shadow to top

* do not prematurely call event handlers during render

* change test to deal with async histogram creation

* left section padding

* lint

* adjust graph to account for top bar,

* lasso tests

* refine histogram tests

* remove testing (onlys)

client/src/components/continuous/continuous.js

@@ -48,7 +48,7 @@ class Continuous extends React.Component {
     }
 
     /* initial value for iterator to simulate index, ranges is an object */
-    let zebra = -1;
+    let zebra = 0;
 
     return (
       <div>