The custom theme dir handling was not working in case the mkdocs config
file was not in the top-level directory. Since mkdocs itself seems only
to work in the top-level directory, this PR modifies mkdocs_semiliterate
to interpret custom theme dirs relative to the current directory.
Also, improves the harmonization between current mkdocs_simple_plugin
code and this code.
Resolves#28.
Reviewed-on: #29
Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Co-committed-by: Glen Whitney <glen@studioinfinity.org>
