move down diagnostic analyzer executor down to workspace layer since all requires one now lives in workspace layer.

Use editorbrowsable options when computing cref descriptions
Share cref description computation code between C#/VB
Etc

Ensure that all *.*proj, *.props, and *.targets files are prefixed with the xml and copyright elements

* moving naming styles types into the workspace layer.
Teaching abstract options serialization service about naming styles.

* Implementing naming styles support for editorconfig

* responding to david's PR feedback

* responding to Jason's feedback

* responding to Jason's feedback part 2

* addressing the latest set of comments from David

* addressing Jason's comments

* addressing Kevin's comments

Rename intenral code to 'FindUsages' so it better reflects that it can present results for more than just FindReferences.