mk_http: Minor fixups for event handling.
mk_plugin: Fix location lookup if path is "/".
mk_request: Add handler member to session_request.
mk_plugin: Set session request handler in location_request().
mk_plugin_next: Reset queue in body_error_page().
mk_filter: Fix error in filter_run() on empty source.
mk_queue: Assert src and dst in mk_queue_move_all().
mk_plugin_next: Add request_abort() plugin hook.
mk_http: Abort requests on error.

End all filters and call request_abort() for aborted requests.
The request_abort() function is only called if a request is currently
handled by a plugin.
static: Don't stream http response.

Static will always known how much data to deliver.
mk_queue: Use separate entries for destructors.
mk_plugin_next: Add body cleanup functions..
mk_plugin_next: Fix connection count of plugin event fd.
mk_http_transport: Fixup of transport init.
mk_http: Set status code for older plugins.
mk_http: Fixup of new abort request and stuff.
mk_http: Fix nonsensical if on request state in mk_http_filter().
mk_http: Don't print error message for EAGAIN.
mk_http: Fixup of sr->handler support.
static: Add cleanup of sent file descriptor.