Introduce DividedStream

[pepelev]

Introduce a stream wrapped that allows to read stream by pieces.

Scenario is as follows:

1. Get a read oriented stream
2. Wrap it into DividedStream with piece size specification
3. Get first piece as Stream
4. Read it as requested but not more than piece size
5. Dispose piece stream
6. Get a next piece
7. Repeat until newly returned piece stream is empty

This is useful when you need to store or work with large stream by pieces.

[pepelev]

It is good to introduce PrefixOf stream that limits the number of bytes that user can read from wrapping stream.