Using default handler for before and after request signals.

In the before_request default handler, the Response object is
initialized. This way, the Response object is still uninitialized for
connected handlers.

In the after_request default handler, the Response body is completed.
This way, anything registered after_request may still edit the body
before it gets completed.

For both, handlers can be connected after using connect_after.
Replaced printing to stderr by real error message using Glib logger.
Default request handler.

When no route matches a request, a default_request signal is called and
is used to produce the appropriate response.

This allow developer to handle themselves 404 errors.
Merge pull request #17 from arteymix/log-using-glib

Replaced printing to stderr by real error message using Glib logger.
Merge pull request #13 from arteymix/complete-response-body-in-default-handler

Using default handler for before and after request signals.
Expose valum from docker on port 3003, some makefile helpers
Merge branch 'signal-when-not-found'

Conflicts:
	src/router.vala
Updated Debian/Ubuntu apt-get string
Listen on 3003. 3000 always conflicts with Rails :)
Expose 3003
Obtain the listened urls from server.get_urls ()

The printed message was originally hard-coded and broke when the sample
app port has changed to 3003.