Update snapshots and readme

Author: lauriejones

README.md

@@ -121,7 +121,7 @@ Optional. A `string` or valid React component. Defaults to `div`.
 
 Controls the width of the grid unit.
 
-A `number` between `0` and `1` OR a `string` of `min` or `max` OR an `object` where the values are `number`s or `string`s for each desired breakpoint. Defaults to `1`.
+A `number` between `0` and `1` OR a `string` of `min` or `max` OR an `object` where the values are a `number` between `0` and `1` OR a `string` of `min` or `max` for each desired breakpoint.
 
 #### visible
 

src/components/__snapshots__/GridUnit.test.jsx.snap

@@ -84,18 +84,18 @@ exports[`GridUnit should render size at different breakpoints 1`] = `
 
 @media (min-width:64.0625em) {
   .c0 {
-    -webkit-flex-basis: 25%;
-    -ms-flex-preferred-size: 25%;
-    flex-basis: 25%;
-    max-width: 25%;
+    -webkit-flex-basis: 0%;
+    -ms-flex-preferred-size: 0%;
+    flex-basis: 0%;
+    max-width: 0%;
   }
 }
 
 <div
   className="c0"
   size={
     Object {
-      "desktop": 0.25,
+      "desktop": 0,
       "mobile": 1,
       "tablet": 0.5,
     }