Titanium CLI ignorefiles

I have added a file in myhook.js in the plugins folder. I have added a small function

/*****FUNCTION START**/

exports.cliVersion = '>=3.X';

exports.init = function (logger, config, cli, appc) {

cli.addHook('build.pre.compile', function (build, finished) {

    logger.info('doing really neat stuff before the build even starts!');

    cli.ignoreDirs = "^(\\.svn|_svn|\\.hk|_hk|\\.git|\\.hg|\\.?[Cc][Vv][Ss]|\\.bzr|\\$RECYCLE\\.BIN)$";

    finished();
});

};

/*****FUNCTION END**/

This function is getting called. I have changed the " cli.ignoreDirs " and added ".hk" to the list. so in my IDE, the ".hk" folder is getting hidden but when I try to build the apk, ".hk" folder is being generated as part of the build. Can anyone plz suggest me as to why ".hk" folder is getting generated. Am I following the correct approach? My requirement is while generating a build I do not want some folders to be generated as part of the build but they should be part of the source folder.

Any help is very much appreciated