fix width on firefox

Author: mmalerba

src/lib/select/select.scss

@@ -10,7 +10,7 @@ $mat-select-panel-max-height: 256px !default;
 $mat-select-item-height: 3em !default;
 
 .mat-select {
-  display: inline-block;
+  //display: inline-block;
   outline: none;
 }