[lib] Added variation checking method in typeface

Author: mta452

tehreer-android/src/main/java/com/mta/tehreer/graphics/Typeface.java

@@ -223,6 +223,15 @@ private void setupNames() {
         }
     }
 
+    /**
+     * Returns <code>true</code> if this typeface supports OpenType font variations.
+     *
+     * @return <code>true</code> if this typeface supports OpenType font variations.
+     */
+    public boolean isVariable() {
+        return variationAxes != null;
+    }
+
     /**
      * Returns a variation instance of this typeface with the specified design coordinates.
      *