Define conventions for options, properties, parameters, etc.

[fgeorges]

Define some conventions (like naming conventions) for options, properties, parameters, etc. For complex parameters, one possibility is to use maps, another one is to use XML elements. There should be conventions for both possibilities, the editor deciding for each module which one to comply to.

Both approaches are legitimate in different contexts, but we want them each to be consistent across modules.

For context, see the minutes of the meeting in Prague in Feb. 2015: https://lists.w3.org/Archives/Public/public-expath/2015Feb/0005.html