Add a super-basic test

Just checks that --help works
Add a trivial test driver
Add proposed boost.process library
Move test-driver to its own subdirectory

Also use alternate method (http://stackoverflow.com/a/10824578/125349)
for updating executables when testing
Actually use Boost.Process to launch svn2git
Use the boost unit test framework
Link test driver with SVN libraries
Create an SVN repository for testing
Improve test naming
Create SVN repo and commit to it