q-fs is deprecated, use q-io/fs instead in doc generators

[ksheedlo]

From Pete's comment on #3235:

The q-fs npm module is now deprecated. We should be using q-io instead. This module contains the function makeTree (see http://documentup.com/kriskowal/q-io#filesystem/maketree-path-mode). I think we should upgrade the project to use this module instead of implementing our own algorithms, which would also need to have unit tests by the way :-)

We need to replace q-fs with q-io/fs. If it meets our needs with respect to building directories (see the later comment), then we should also replace writer.makeDir with q-io/fs.makeTree. If it doesn't, then we should at least include tests for writer.makeDir.

[evankroske]

It appears that we're not using q-fs anymore. Could you confirm this and close the bug?

[caitp]

This was dealt with by 18e0768 in core. I'm not sure anything in the tree needs q-fs, or q at all anymore. I'm wrong, i18n still wants q