* Buffer

* Buffer
  - new pimpled TocBackend member and associated accessors.

* toc.[Ch]: delete all toc related methods except outline.

* TocBackend:
  - goTo(): deleted, this gets rid of the LyXView dependency
  - made all accessors const.

* ControlToc:
  - rework the controller to work exclusively with TocBackend.
  - goTo(): now call LyXView::dispatch() directly

all other files: update with the TocBackend or ControlToc API changes.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15852 a592a061-630c-0410-9148-cb99ea01b6c8