Improve the Plugins documentation for referencability
Promote reference section to its own section, out from "advanced". Add parameter details for methods.
line-wrapping
More formatting, editting
Clarify which attributes and methods are for the CMSPluginBase and which are for CMSPlugin. Add copy_relations and post_copy methods.
More details on post_copy
Merge pull request #2932 from mkoistinen/doc_fixes

Improve the Plugins documentation for referencability