upgrade serving
simplify xml header in wms templates

remove encoding (utf8 by default anyways) to allow lxml to
parse it as string (instead of byte) in tests
decode request args
fix comparison of wms version
fix header encoding and content-length
fix wms tests

send dummy body as bytes and use bbox aware query comparator
vendorize werkzeug.serving
fix bbox comparison
fix url parse imports in demo page
fix iteration on tile_layers
fix raise exception in tempita
add missing import
fix tempita for python 2
fix etag calculation in kml test
simplify xml header in kml docs
fix encoding errors on empty responses
check for new xml header in wms exceptions
skip mapproxy-util system tests on PY3 for now
fix bool(CacheInfo) on PY3
decode headers from CGI