Moved the contents of the doc/Releasing.txt to the "Creating a Release" page on Github
Move the tools out of bixo-core to a separate sub project "tools".

This was the core library is just the toolkit and no tools are included.
Switch to using slf4j for all logging in bixo-core.

For now use cascading.utils 2.2-SNAPSHOT - which has also been updated
to only use slf4j for logging.
Any app/tool making use of bixo-core or cascading.utils will have to
pull in the appropriate binding library for slf4j-api.
Include slf4j-log4j12 and log4j for the examples, contrib and tools.