Revert "fix issue with mug.parentMug"

This reverts commit ffecf2158023ce8610128476e3dab6939ce72cc6.

Conflicts:
	dist/vellum.min.js
refactoring to undo the previous revert of a fix

This refactors some stuff in the question adding methods.  One effect is
that questions are no longer added based on the currently-selected mug,
instead it's explicitly passed.  This should make loading a form faster.
Merge pull request #82 from mwhite/fix

fix issue in previous release
Merge branch 'develop' of github.com:dimagi/Vellum into develop
fix issue on empty forms
Merge branch 'develop'
Merge pull request #172 from mwhite/master

fix issue in previous release