Initial steps to make Maven project modular

* markdownj-core is the core MarkdownJ functionality.
* MarkdownFilter has been moved to a new markdownj-ant-utils module.
* ant dependency pushed down to markdownj-ant-utils module.
* This should allow for development of future MarkdownJ integration
  modules (e.g. full HTML-page generation, Ruby or dynamic lang.
  integration, etc.), while keeping the core to core Markdown->XHTML
  conversion functionality.
More descriptive module names, add descriptions

Signed-off-by: Alex Coles <alex@alexcolesportfolio.com>
Fix output of site/javadocs to gh-pages submodule

* Requires a some hackery with Maven properties when using
  multi-module projects. See:
  http://stackoverflow.com/questions/465777/nested-maven-properties-evaluated-in-refering-pom-rather-than-defining-pom/1049971#1049971

Signed-off-by: Alex Coles <alex@alexcolesportfolio.com>
Actually add generated javadocs to site

Signed-off-by: Alex Coles <alex@alexcolesportfolio.com>
Rename com.petebevin.markdown package to org.markdownj

* Deprecate com.petebevin.markdown.MarkdownProcessor.

Signed-off-by: Alex Coles <alex@alexcolesportfolio.com>