Fixed CRUD actions with ST models + Parse REST API

Parse REST API sends its response wrapped in a “results” node if the
GET is to a collection of objects. If its any CRUD to a particular
object, it sends results back in just an object {} without wrapping it
in “results” node. As a default we set Sencha Touch’s proxy’s reader’s
rootProperty to “results”, but that means when a CRUD happens to a
single record, the changes from Parse are not synced to the local copy
automatically – we need to do it explicitly. That is done in Common.js.
Fixed scrolling of list behind floating tab bars with spacer components.