add "spec.add_dependency 'mruby-time'"
win32ole_record.c: Fix inefficient code
win32ole.c: The Time class in mruby does not support nsec method
test/ruby-test/*: mruby doesn't have 'defined?' method. Use const_defined?(:...) instead of 'defined?'
test/ruby-test/test_win32ole_variant.rb: mruby seems not having $!
test/ruby-test/test_win32ole_variant.rb: Time#strftime method does not exist in mruby