[unit-test] allow imports in test using sciter.import

[unit-test] show test window id showTest attribute set in link [unit-test] activate test tool window on shift+ctrl+T [unit-test] support beforeEach, afterEach test functions

Hello Andrew, This merge fixes some of the unit-test issues from here https://sciter.com/forums/topic/request-for-information-on-sciter-js-test-automation/