docs(docs/upgrading-to-4.jmd): #867 - upgrading / breaking-changes doc stub

[skip ci]
docs(docs/upgrading-to-4.jmd): #867 - upgrading / breaking-changes doc stub

[skip ci]
docs(docs/index.jmd): #867 - breaking changes note

[skip ci]
docs(docs/features/styling.jmd): #867 - note about element options

[skip ci]
feat(*): #867 - dragAndDrop.disableDefaultDropzone is now redundant
feat(*): #867 - dropzone visibility now tied to presence of qq-hide-dropzone attr
docs(docs/upgrading-to-4.jmd): #867 - more DnD placeholders on upgrading page

[skip ci]
feat(client/js/templating.js): #867 - remove drop zone if DnD not supported
docs(*): Show current version on each page [ci skip]
fix(client/js/uploader.js): #867 - remove non-existent prop from templating module init
docs(client/js/templating.js): #867 - comments mostly
fix(docs/*): Remove link to git tag

Because the tag only lines up correctly on master. Every other tag
would theoretically link to a non-existent github tag since we don't
tag releases when we start work on a release, but when we end.

[ci skip]
fix(docs/features/drag-and-drop): Incorrect hideDropzones default value

Is now `true`.

[skip ci]
fix(lib/modules.js): syntax error
fix(Gruntfile.coffee): actually include the default template file in the dist/build
docs(*): #867 - Template inclusion reminders

[skip ci]
docs(docs/features/styling.jmd): closes #867 - Add buttonFocus & hover classes [skip ci]
Merge branch 'feature/templating-redesign' into develop
docs(docs/modes/ui.jmd): #867 - link to styling in UI overview
docs(docs/upgrading-to-4.jmd): #867 - breaking changes
[skip ci]