templates: Use uri_for to reference static paths.

This commit is provided by (zsh syntax):

sed -i 's|/static[^"]*|[% c.uri_for("&") %]|;s/\[% size %\]/${size}/' **/*.tt

And the reason for this change is to make it easier to change the base
path with headers like X-Request-Base to be served within a URI prefix,
especially when behind a reverse proxy.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
hydra-module: Allow to specify the listen host.

It's currently possible to specify the port but not the address or
interface you want to listen on.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Warn against multiple jobs with the same name
Handle UTF-8 characters in eval error messages
Distinguish between permanent evaluation errors and transient input errors

Fixes #112.