Hi. I just started a clone of some features of Org mode to the markdown mode of a commercial editor (Sublime Text 2); it's available at https://github.com/demon386/SmartMarkdown
It's based on Python and until now I haven't referred to the implementation of Org. However, plan-text table is very challenging and I'm prepared to refer to the implementation of Org. I'm not very clear about the license issue in this case. Currently the plugin is licensed under MIT license. Is it necessary for me to release the plugin under GPL? Thanks.