fix doc linking to not use URLs

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

README.md

@@ -36,10 +36,10 @@ WARNING: the development branch is filled with lava, fear and capitalism.
 
 # Further Docs
 
-[Usage](https://github.com/grufwub/gophor/blob/master/docs/USAGE.md)
+[Usage](docs/USAGE.md)
 
-[CGI compliance](https://github.com/grufwub/gophor/blob/master/docs/CGI.md)
+[CGI compliance](docs/CGI.md)
 
-[Gopher specific information](https://github.com/grufwub/gophor/blob/master/docs/GOPHER.md)
+[Gopher specific information](docs/GOPHER.md)
 
-[Extra notes](https://github.com/grufwub/gophor/blob/master/docs/MISC.md)
+[Extra notes](docs/MISC.md)