fix(datepicker): fix oblong open button.

Author: jelbourn

src/components/datepicker/datePicker.scss

@@ -118,6 +118,7 @@ $md-date-arrow-size: 5px;
 // Only apply this high specifiy to the property we need to override.
 .md-datepicker-triangle-button.md-button.md-icon-button {
   height: 100%;
+  width: 36px;
   position: absolute;
 }