Added SVN driver
Added SVN driver

Added SVN driver to available drivers - some of the function names don't
quite match with the command being run.
Credentials are loaded from `SVN_USERNAME` and `SVN_PASSWORD` environment variables.

Kareo/Hound,flowbywind/hound,Kareo/Hound,dnephin/hound,morria/hound,snowsnail/hound,sstarcher/Hound,gwindes/Hound,Kareo/Hound,morria/hound,gwindes/Hound,rberrelleza/hound,mrKrizz/hound,flowbywind/hound,dnephin/hound,snowsnail/hound,colbyr/hound,mrKrizz/hound,etsy/Hound,dnephin/hound,miketheman/hound,snowsnail/hound,flowbywind/hound,sstarcher/Hound,rberrelleza/hound,morria/hound,mrKrizz/hound,miketheman/hound,matthewdoerksen-porch/Hound,etsy/Hound,sstarcher/Hound,rberrelleza/hound,morria/hound,etsy/Hound,Kareo/Hound,miketheman/hound,flowbywind/hound,snowsnail/hound,matthewdoerksen-porch/Hound,colbyr/hound,etsy/Hound,matthewdoerksen-porch/Hound,0xmohit/hound,rberrelleza/hound,matthewdoerksen-porch/Hound,gwindes/Hound,colbyr/hound,0xmohit/hound,0xmohit/hound,miketheman/hound,0xmohit/hound,dnephin/hound,mrKrizz/hound,Kareo/Hound,gwindes/Hound,colbyr/hound,sstarcher/Hound