add 2nd test to command_builder_spec
remove redundant test
add more BillingLogic::CommandBuilders::ActionObject tests
add more tests (including two that appear to surface bugs
add another test of two products
clean up some of my new tests; add definition of IndependentPaymentStrategy
remove passing test that tested something not used; remove unneeded Timecop
rename two tests
extract duplicated strftime to class constant
refactor long #to_s method
command_builders.rb refactoring
rename STRFTIME -> DATE_FORMAT
Merge pull request #19 from JamesLavin/56375826-refactorings

56375826 refactorings
rename tests to make clearer what they're doing
Merge pull request #18 from JamesLavin/56381388-test-improvements

56381388 test improvements