issue0001: download queue

Change-Id: I2bdc98e73c29c2bb0c797dd62dd722232f65886d
issuse0002: cancel download stuck

1. The download service call transfer api cancel sync, that will stuck, change it to async.
2. modify test to download file to tmp dir.
3. fix build script.

Change-Id: I1bf12aadf7c12f77b9ed841d738da6c2a456a2e5
issue0003: md5 & file size verfiy

1.verify file md5 when download end, if md5 is mismatch, task will be cancel
2.check the fileSize of input, if the fileSize is set, the download service will not query remote file size before download
3.fixbug: delete the work queue instead wait queue when download finish

Change-Id: I34101b452fd813626f21662630bb1887c687eee6