100 instead of 1000 on the exception raised when the price is below 100. (#6)

Author: Kepsondiaz

src/Invoice/InvoiceItem.php

@@ -59,7 +59,7 @@ public function setPrice($price)
         }
         else 
         {
-            throw new Exception('Price must be a number and greather than 1000 !');
+            throw new Exception('Price must be a number and greather than 100 !');
         }
     }