Also, generate password randomly if not provided instead of using an
hardcoded value.
Publish them as they can be generated internally.

  This may fix compilation on ARM devices.

Conflicts:
	component/glibmm/buildout.cfg
	component/gtkmm/buildout.cfg
	component/inkscape/buildout.cfg
	component/libsigc/buildout.cfg
	stack/erp5/buildout.cfg

they seem not required in Ubuntu 13.10 but required in openSUSE 12.1.

urllib chooses the proper httplib class based on url scheme, so use it.
urllib handles in-url credentials for basic auth, removing the need to
implement it ourselves.
Simplifies URL parsing, uncovering errors on recipe execution rather than
on generated script's execution.
Use %r for automated escaping & quoting.