Refactor Transfer

Now Transfer is a single service, erery download request would be
a transfer struct.

1. transfer service will exit afer 60s without download.
2. if download failed, the transfer will retry 3 times by default.
3. all net request start by go routinue, by default, only on thread is
active for download

Change-Id: Ia6b96253fc07efe60b4e53a9b1c004f419248328
issue0020: fix-status-file-WriteAt-lost-data

when use file.WriteAt to write data, the last some bytes will be lost
so instead with ioutil.WriteFile

Change-Id: I03cd34d5acbb55a3de9bf7937b110fc64451d13a
repackaging

  * add LICENSE
  * make myself as maintainer

Change-Id: I76c693116de95d13aa1de8cd751ed0bb33a309b2
issue0021: Cancel Task When Call dbus inferface failed

Change-Id: I921fe2501be374c36d76be67359a30f63d948492
isue0022: remove dbus signal lost fix

the go-dlib has fix the bug that lost signal, so remove the fix code
deal with signal lost.

Change-Id: Ida5f868d86651a5ae34d0d4994b485917b50707f
issue0023: add test file

1. add uint test under src/pkg.linuxdeepin.com/service &
src/pkg.linuxdeepin.com/transfer
2. add pre test script under misc/test
3. test tmp file would be store under /misc/test/tmp
4. add test target to Makefile
5. add vsftpd servier to test

Change-Id: I2fbfb7ef29fe374f0c6ed15baff70797222782b2