account/abi: implements event parsing

Implementation of basic event parsing and its input types. This
separates methods and events and fixes an issue with go type parsing and
validation.

accounts/abi/type.go

@@ -218,5 +218,5 @@ func (t Type) pack(v interface{}) ([]byte, error) {
 		}
 	}
 
-	return nil, fmt.Errorf("ABI: bad input given %T", value.Kind())
+	return nil, fmt.Errorf("ABI: bad input given %v", value.Kind())
 }