Introduce the Doxygen documentation process in the source base

[jfournier]

Steps to slowly introduce the Doxygen process in the code base:

1. Write down a simple process for developers to follow (in progress)
2. Include documentation examples with the process (source and header templates)
3. Have the developers apply this documentation process to their code
4. Produce a Doxyfile and 'make docs' rules
5. Get nightly generation of the html documentation and published on the developer site under the manual section (including the doxy_warn.log to fix documentation issues)

Welcome any other suggestions!

[jfournier]

6. Include a template for a better Main Overview page (e.g. descriptions, link to the public SAF API documentation, link to the internal OpenSAF implementation documentation, development processes etc.)