server: better reverse proxy headers handling: reverse proxy header were not used if `X-Forwarded-Host` was not set, with this patch `X-Forwarded-Host` and `X-Forwarded-Proto` are check independently. Furthermore, the new standardised `Forwarded` header is not checked too. fix 396

import os.path

version_file = os.path.join(os.path.dirname(__file__), "VERSION")
with open(version_file) as f:
    __version__ = f.read().strip()