frontends/controllers/ControlBibtex.[Ch]: new members bibtotoc(), getStylefile(),

frontends/controllers/ControlBibtex.[Ch]: new members bibtotoc(), getStylefile(),
	which hold functionality that has been moved from the frontends
	and implement a method to use a default stylefile for new bibtex
	insets (bug 2322).

frontends/gtk/GBibtex.C:
frontends/qt2/QBibtex.C:
frontends/qt4/QBibtex.C:
frontends/xforms/FormBibTex.C: Move parsing of Options (stylefile, bibtotoc) to the
	controller (bug 2322).

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@13427 a592a061-630c-0410-9148-cb99ea01b6c8