Added IDownloadProcessFinishedCallback interface;
Added finished callback arraylist to DownloadAsyncCommunicator;
Added executeDownloadAsyncCommunicator method to communicator;
Added Downloadservice;
Added DownloadPackage class;
Added arraylist of downloadpackages to sharedobjecthelper;
Added md5sum to downloadresponse;
Added hashtable <string, downloadpackage> to sharedobjecthelper (key = md5sum);