#5 It should be easy to call JSeq from another program

[Henrik Arro]

The only way right now to use JSeq to create a sequence diagram from another program i to call Main.main with a number of command-line arguments. The diagram is always written to a file.

We should make it easier to JSeq from another program, by providing set methods for all command-line arguments, and by making it possible to return the diagram as an object, not only through files.