FWBase - Add to support pause/resume download [1/2]

We add pause and resume API here so that application can
pause and resume downloads manually by DownloadManager.
This contains two points:
1. add pause and resume download APIs.
2. add another paused reason for this download status.

PS2/3:
* Fix code.

Change-Id: I8e7878312c1301aebe5dc4bc5e25ad2197e15741
Signed-off-by: MURA Stefano [STELIX PippoX3] <ssspinni@gmail.com>