Metacat

Modifications to make the build more readily find locally installed versions of
sphinx-build, and to remove the unneccary 'html' directory; output of
admindoc is now written directly into build/docs.

Added links to Javadoc. Tuned the layout a bit.

Moving Metacat Sphinx RST documentation from docs/dev to docs/user directory.

Updating Sphinx doc structure in prep for moving metacat admin guide to Sphinx.

Begin process of migrating Admin guide to Sphinx. Structure is now set up, but
content needs to be copied.