Resume stream upload

[nikithauc]

fixes #452

Problem -
*StreamUpload.sliceFile function reads the first n bytes from the Stream.

• If an upload fails after the 0 - n is read from the stream, then on upload resume the sliceFile function reads from n+1 bytes and 0-n is never uploaded.

Solution -

• Added ChunkRecord interface which keeps track of the previous slice and range.
• Compare the new upload range with the previous range and read the bytes accordingly.