CLOUDSTACK-713: Limit Resources(CPU and Memory) to domain/accounts

Addition of two new resource types i.e. CPU and Memory in the existing pool of
resource types.
Added some methods to set the limits on these resources using updateResourceLimit
API command and to get a count using updateResourceCount. Also added calls in the
Virtual machine life cycle to check these limits and to increment/decrement the new
resource types

Resource Name  :: Resource type number
    CPU               8
    Memory            9

Also added Unit Tests for the same.