soup-server: document message processing a bit more
soup-server: document message processing a bit more

jwendell/libsoup,fanc999/libsoup,jwendell/libsoup,jwendell/libsoup,jwendell/libsoup,fanc999/libsoup,fanc999/libsoup,fanc999/libsoup,jwendell/libsoup,fanc999/libsoup