feat(plugin): Add clear-left, clear-right, clear-both classes

Added clear-left, clear-right and clear-both classes to float.js

Implements #1050

Author: Dan Gayle

src/plugins/float.js

@@ -5,6 +5,9 @@ export default function() {
         '.float-right': { float: 'right' },
         '.float-left': { float: 'left' },
         '.float-none': { float: 'none' },
+        '.clear-left': { clear: 'left' },
+        '.clear-right': { clear: 'right' },
+        '.clear-both': { clear: 'both' },
         '.clearfix:after': {
           content: '""',
           display: 'table',