Meta Issue Description todo: - Update the requirements list, showing potential callback signatures (as discussed in the ['[FT-plugins] Proposed "Features'](http://lists.geany.org/pipermail/devel/2016-August/010093.html) on the mailing list). - Update the signatures proposed for at least sidebar symbol tree, and most likely auto-completion and calltips to have the ft-plugin provide information to Geany using TMTag structures (as [mentioned](http://lists.geany.org/pipermail/devel/2016-August/010120.html) in the same thread as above). - Add more details about underlying basic implementation strategy once fleshed-out more on the mailing list ["Proposed Design"](http://lists.geany.org/pipermail/devel/2016-August/010088.html) thread). - Remove "Development/Contribution Strategy" section. @b4n confirmed it's OK to make a new branch, and we will have to see how it goes with keeping the changes in-sync with master branch. - Replace the "Discussion Guidelines" with a simple note about not polluting this particular Github issue, and using the mailing list instead.