RevikiLicencing - from [uncommitted] to r529

The reviki source code itself is licenced under the [[http://www.apache.org/licenses/LICENSE-2.0.html|Apache 2.0 licence]].

A number of open source libraries are used by reviki, not all of which are available under the same licence. These are detailed in the [[http://svn.reviki.org/svn/reviki/trunk/NOTICE|NOTICE]] file in root of the source tree.