Test away

I got Steve-from-the-Forum's boost unit test skeleton code compiling and running, so there's now a src/test directory and you can 'make -f makefile.unix test_bitcoin'

More tests are very welcome. I'd welcome higher-level tests (not just code unit tests), too.

And speaking of testing: if you know a good QA test manager type person interested in bitcoin, I think we can wrangle up funding for somebody to put together a team to help test bitcoin (and hopefully pull requests). I think lack of testing resources for core bitocin is a big weakness right now.