Add test case:popup-tip(height)
Add test case:popup-tip(scroll-bar,min-height)
Add test case:popup-menu*,popup-cascade-menu
Add test case:popup-next,popup-previous,popup-select
Add test case:popup-scroll-down,popup-scroll-up
Replace popup-test-with-create-popup to popup-create
Replace helper functions for some tests.
* popup-test-helper-get-overlays-buffer to popup-test-helper-buffer-contents
* popup-test-helper-match-points to popup-test-helper-rectangle-match
Change buffer-contents from string to propertied string for detecting end of popup.
Refactoring all test cases
Add test for #18, #19, #20
Merge pull request #23 from uk-ar/uk-ar-add-test-case

Port test from popup-interactive-test.el