(HI-289) expand Hiera basic functionality acceptance tests

(HI-289) expand basic functionality acceptance tests  
three tests added:
  lookup_data_no_options - tests a simple priority lookup of a string from
    CLI
  default_value_if_key_not_found tests - that default value is used when
    key not found from CLI
  check_first_backend_hierarchy_first - tests multiple backends to ensure
    each hierarchy is checked in order as in the config file

(HI-289) expand basic functionality tests to work in windows and
solaris11.
make tests more atomic and remove 00-setup.rb
This block defines the agent as 'a'. However, this line inherits the 'agent' from the outer block. Is this intentional?