More examples and API documentation

Attached is a compressed diff with some more examples. All appenders, layouts, configurators and filters now have an example which is linked in the phpdoc of that class.
The appenders have it linked into the appenders.apt as well.

BTW, look at the class phpdoc of e.g. LoggerConfiguratorXml, I can do inline examples now! This just raises the question if we really need the whole Apache Licence in every
examples/.php and examples/.properties because it would bloat the phpdoc quite much (I can't use "BEGIN SNIPPED: foo" in phpdoc). Maybe just a @copyright line is enough for so small snippets?

bye,

christian