Allow require of directory to find directory/index.js

[patgoley]

Standard node require behavior will look for somePath and also somePath/index.js, so NodeKit should probably do the same.

I'm thinking the js implementation of require should be updated to the following:

BootstrapModule.prototype.require = function(id)
{
    if (id == 'native_module') {
        return BootstrapModule;
    }

    if (id[0] == ".")
    {
        id = _absolutePath(this.__dirname + '/', id);
    }

    var cached;

    var isPossibleDirectoryRequire = id.indexOf('index.js') == -1;
    var directoryIndexId = id + '/index.js';

    if (isPossibleDirectoryRequire) {

        cached = BootstrapModule.getCached(directoryIndexId);

        if (cached) {
            return cached.exports
        }
    }

    var cached = BootstrapModule.getCached(id);
    if (cached) {
        return cached.exports;
    }

    process.moduleLoadList.push('BootstrapModule ' + id);

    var bootstrapModule = new BootstrapModule(id);

    bootstrapModule.cache();

    bootstrapModule.load();

    if (Object.keys(bootstrapModule.exports).length == 0 && isPossibleDirectoryRequire {

        return BootstrapModule.require(directoryIndexId)
    }

    return bootstrapModule.exports;
};