Add a quick fix for page titles
Add basic support for meta-data in external files.

Using the command-line option `--meta`, you can now specify a file to use for loading meta-data key/value pairs, using the same basic syntax as Multimarkdown. Currently this can be used to set the page title (otherwise set by finding the top-most heading), and to add CSS styles to the output page.

This commit doesn't add support for Multimarkdown style meta-data within the documents themselves; all the meta-data has to come from the file specified with `--meta`.
moved Makefile to top level
add rudimentary packaging script