Support to show upload progress in realtime

Changes:

3511db4 Add demo url
a98b4fe Include debug params to example command
9d83ec4 Fix merge conflicts
f817a60 Merge pull request #2 from AndreLion/upload-progress-callback
a59d47f Fix issue: can't get progress when upload file
1f5f34a change variable names
111fa82 support onprogress callback to fetch upload progress
70104e3 Add progress callback
d5b6c23 Add bluebird to README
9fc6773 Merge pull request #1 from AndreLion/patch-1
760dc51 fix typo