This is very handy in Unix world as most applications have standard
installation paths and standard command-line names. Hence, we can now
use those plugins without altering the site.yaml file at all.

Includes the patch by Brian Mattern that fixes menu to work in all
situations. Also adds the explanation how to use media_url and
base_url properties.

By default, Markdown is building XHTML. If you do an HTML5 website, it
can therefore generate invalid markups (for example <th /> is not
valid in HTML5). Markdown can be configured with "output_format". This
patch adds this configuration switch to Hyde:

```
markdown:
  extensions:
    - codehilite
    - extra
    - toc
  output_format: html
```

Attach all post resources to all page resources.  Now `hyde gen' works.  Also
fix up a couple of the unit tests.

Configured in a resource's metadata, creates copies of that resource, each of
which will receive its own `page' containing a distinct list of `posts'.

is present in the target directory. (Issue #21)
*   Bug Fix: Exceptions are now handled with `ArgumentParser.error`.
    (Issue #21)