Make ways_soap_srv handle requests in parallel
Make ways_soap_srv handle requests in parallel

This change makes the yaws_soap_srv:handler/4 function call the
request/5 function directly, instead of having the gen_server do
that. This avoids blocking the gen_server when handling requests and
should provide much better parallelism.

The gen_server now only manages WSDL models. The handler function will
call the gen_server in order to retrieve the model. The rest should now
be executed in the regular Yaws workers.

weisslj/yaws,sebgod/yaws,klacke/yaws,klacke/yaws,leoliu/yaws,sebgod/yaws,phonohawk/yaws,leoliu/yaws,sebgod/yaws,klacke/yaws,weisslj/yaws,leoliu/yaws,klacke/yaws,leoliu/yaws,bsmr-erlang/yaws,bsmr-erlang/yaws,phonohawk/yaws,weisslj/yaws,bsmr-erlang/yaws,bsmr-erlang/yaws,sebgod/yaws,phonohawk/yaws,klacke/yaws,weisslj/yaws,sebgod/yaws,bsmr-erlang/yaws,phonohawk/yaws,weisslj/yaws,leoliu/yaws,klacke/yaws,weisslj/yaws,bsmr-erlang/yaws,leoliu/yaws,phonohawk/yaws,sebgod/yaws,sebgod/yaws,bsmr-erlang/yaws,phonohawk/yaws,phonohawk/yaws,klacke/yaws,weisslj/yaws,leoliu/yaws