devwsys is now wsys

Rio is a file server which provides virtual devices, but it is not called a device. Other file servers offer some other files which can be mounted on /dev, but they are not called devices either. P9p's devdraw is the exception, not the norm and, therefore, devwsys has been renamed to wsys.

For the moment, the code has not moved from its usual location: https://bitbucket.org/yiyus/devwsys-prev

There has been several improvements since the end of GSoC. Check the changelog.