scroll alias for scrollTo
add get_scrollX and get_scrollY, along with their aliases: pageXOffset and
pageYOffset. These always return 0, unless scroll or scrollTo are called.
Fix events.get_timeStamp (was events.get_timestamp, wrong casing).
Rename `newRunner` to `htmlRunner`.
move tests to src/tests (from src/browser/tests). src/runtime and possibly other
parts might want to have html tests too.