DownloadProvider: add to support pause/resume download by manual

This feature contains below points:
1. add to pause running download by manual.
2. add to resume manuallly paused download by manual.
3. add to show proper contents in notification and download-list
   for manually paused status.
4. add to support download breakpoint continuing when HTTP server
   doesn't contain etag in response header. Android baseline only
   supports this when etag is not null.
5. add to show proper contents in notification and download-list
   for status of waiting-for-network.

Change-Id: I433cdee2de8b3add0248bbb0a9d02f8da4e5bb38
Add Download Speeds in notification

This commit adds the ability to show the current total download speed

Screenshots: http://goo.gl/M3eRNR

ps7 : remove download site, and make speed to bit/sec
ps8 : make speed to byte/sec and cleanup
ps9 : revert to B/sec
ps10: fix some formatting issues
ps13: rebased

Change-Id: I801dbe61c7ee59d0c1d14d5851ad6dc3a7678499
Automatic translation import

Change-Id: Ia7a31ee88626ea019884a943749b256dd668d281