Wrong mode for node.js

[marklagendijk]

Sorry that I am not doing this via a pull request, but I don't know how to use Git yet.
less.mode is set to 'rhino' when using node.js:

if (typeof environment === "object" && ({}).toString.call(environment) === "[object Environment]") {
    // Rhino
    // Details on how to detect Rhino: https://github.com/ringo/ringojs/issues/88
    less = {};
    tree = less.tree = {};
    less.mode = 'rhino';
} else if (typeof(window) === 'undefined') {
    // Node.js
    less = exports,
    tree = require('./tree');
    less.mode = 'rhino';
} 

I don't know what the implications of this bug are.

[cloudhead]

Nice catch, it doesn't seem to have any effect, because the import function is overwritten in index.js, which makes me wonder what the point of this check actually is. Nevertheless, fixed it. Thanks.