[CDE-395] When a new dashboard is created, the renderer type should be b...

...ootstrap by default

	- empty.wcdf ( read: the wcdf that holds the basic parameters for a new dashboard ) now includes the rendererType ( set to 'bootstrap' )
	- updated cde-core's cdf-dd-layout failsafe mechanism for rendererType definition from 'blueprint' to 'dashboard'
	- documentation @ http://redmine.webdetails.org/projects/cde/wiki/Setting_up_the_default_renderer_for_new_CDE_Dashboards