Consider loosening restriction on output dir attribute

[joeytakeda]

I have a site with multiple search pages, and I would like all of their outputs to go into a subdirectory (e.g. search/en and search/fr). You can do that in the config like so:

      <output dir="search/fr"/>

But that invalidates the config, since "value of attribute "dir" is invalid; must be an XML name without colons". I think we just need to change this to a directory path (so the same datatype as stemmer/@dir).

[martindholmes]

@joeytakeda This makes perfect sense to me.