* template/custom env var fix:
- ensure pywb.host_prefix, pywb.app_prefix and pywb.static_prefix set for all requests via prepare_env()
- ensure X-Forwarded-Proto is accounted for in pywb.host_prefix
- call prepare_env() in handle_request(), and also in rewriterapp (in case using a different front-end app).
* update wombat to 3.3.6 (includes partial fix for #684)
* bump version to 2.6.3