Are there any command line options supported?

Yes. You can pass '-zlui <ui-type>' option, where <ui-type> should me one of gtk, qt or qt4. (This option is not supported in newest beta 0.99 releases.)

You also can pass '-lang <lang-code>' option, where <lang-code> is a standard 2-letter language code, to specify interface language.

And of course you can pass a name of file that you want to open.