Allow to have dots on names and namespaces

According to http://wiki.commonjs.org/wiki/Packages/1.0, dots are allowed to be used on CommonJS packages names. This change use slashes (that's a not allowed character) to be used as namespaces separator and restored the previous behaviour by just removing the dots. An alternative, more compliant option would be to allow to use them in the namespaces names, but this would require to access to them using brackets instead of object notation.