adding color_from_rating()

src/message_api.cc

@@ -55,6 +55,11 @@ namespace pEp {
             Message dst(_dst);
             return make_tuple(dst, keylist, rating, flags);
         }
+
+        int color_from_rating(int rating)
+        {
+            return (int) ::color_from_rating((PEP_rating) rating);
+        }
     }
 }
 

src/message_api.hh

@@ -7,6 +7,7 @@ namespace pEp {
         Message encrypt_message(Message src, list extra = list(),
                 int enc_format = 4, int flags = 0);
         tuple decrypt_message(Message src);
+        int color_from_rating(int rating);
     }
 }
 

src/pEpmodule.cc

@@ -193,6 +193,7 @@ BOOST_PYTHON_MODULE(pEp)
 
     def("encrypt_message", &encrypt_message, "encrypt message in memory");
     def("decrypt_message", &decrypt_message, "decrypt message in memory");
+    def("color_from_rating", &color_from_rating, "calculate color value");
 
     // key sync API