add the possibility to have # comments in a @file

When using the @file possibilities of jcommander it would be useful to have the ability to comment certain lines.


with this pull request this is possible:


(use ```@Parameters(separators = "=")```to have nicer config files ;-) )



and how you use it:

```properties
#Specifiy the port
-port = 42
#Specify another param
--mod1Param = file1
```