Make "Options" a heading

[sils]

See http://api.coala.io/en/latest/Developers/coala_settings.html would be nice to have "Options", "Positional Arguments" etc. headers so they're linkable and give the document some structure

[dpryan79]

FYI, I'm working on this now in the features/implement46 branch. It's mostly functional at this point, feel free to give it a try. One of the current issues is that one can't always link to groups of arguments if their header is duplicated (e.g., in a sub-commands with partially overlapping argument groups).

[dpryan79]

This is now implemented in the develop branch and will be included in the next release.