Android appender

Here's the android appender I promised. I have added all the extra log levels and a mapping to where I think they fit on the android log scale (no real idea about report/trace - correct me if I'm mistaken but I've put them as debug level logs).

It's a bit repetitive and naff in the condp, but java interop doesn't lend itself nicely to normal function mappings without writing a macro and the result isn't ridiculously verbose, so I left it as simple as possible, anything else I tried simply obscured the intention!