moved babysitter and wreqr to devDependencies again (see pull #677)

Installing marionette through bower will also install backbone.wreqr and backbone.babysitter, which is unnecessary since lib/backbone.marionette.js includes them already.
EDIT:
Turns out that #860 broke the original fix #677
Current (1.6.4) core amd version includes wreqr/babysitter as dependencies so both amd and non-amd  bower installs should be ok with this. (fingers crossed)