create an infrastructure / skeleton for adding OGC formats
This was basically done when the WMS GetCapabilities parser was created.
We have a base class for XML parsing: https://github.com/openlayers/ol3/blob/master/src/ol/parser/xml.js
We have a base class for Versioned OGC Formats (where the library supports multiple versions and the correct parser can be chosen automatically based on the output XML): https://github.com/openlayers/ol3/blob/master/src/ol/parser/ogc/versioned.js
We have a parser for exception formats (for generic exception handling) just like in OL2: https://github.com/openlayers/ol3/blob/master/src/ol/parser/ogc/exceptionreport.js
To see an implementation of a versioned OGC parser please check out:
We use constants to decide what versions of the parsers need to be included in the build, e.g. ol.ENABLE_WMSCAPS_1_1_0