ListContainer and empty backing list

The ListContainer(Collection<T>) constructor is dangerous and perhaps
should be deprecated.  If the backing list is empty, an
IndexOutOfBoundsException will be thrown in the getDynaClass method when
properties are accessed.  See the testEmptyList method I added to
DynaBeanBasedContainer test.
I added a (Class<T>, Collection<T>) constructor (ala BeanItemContainer)
and made a slight mod to setCollection that allows the empty list to be
the backing list rather than creating a new empty list (it surprised me,
but isAssignableFrom appears to return false for empty lists).
Merge pull request #8 from jdryan1/listcontainer_empty_backinglist

ListContainer and empty backing list
Added fluent method
Empty list without explicitly given entity type class now reports 0 properties instead of throwing