added spec examples
added monkey pathes on Array, Integer and Numeric
renamed methods #one, #one? to #dimension_one, #dimension_one?
added unitless composite units example
removed array monkey patch method #map-hash
added #to_s, #unitless? methods
removed pending status from specs. using examples from shared context
#base_value is now public. added #unitless? method
added naming specs for multiplication, power