live rewrite: proxy setup refactor: ignore_proxy flag, pass proxy during constructor only
proxy testing: refactored test server thread into ServerThreadRunner
class which runs a server in a seperate thread.. used by http/s proxies
as well, as mock live server proxy
add test for live rewrite with proxy, covering simple case as well as
video
tests rangecache: added integration tests for range support via range
cache, using enable_cache option