Replace deque in StreamReader with bytearray

[asvetlov]

bytearray is highly optimized for appending to the right and removing from the left.
On resizing it keeps up to 50% free space at the begin of buffer before performing a memory reallocation.

[spcharc]

bytearray is doing a great work on appending to the right, but removing from left and resizing? I don't understand. pop(0) is the same with lists
memoryview does not support resizing either.

[asvetlov]

@spcharc it would be nice if you re-read PyByteArray_Resize implementation before posting anything.

[spcharc]

@asvetlov Read the function for 2 hrs, did a lot of search, and failed to understand. I hope I can read C code one day. I won't bother you anymore then.

[serhiy-storchaka]

See https://bugs.python.org/issue19087.

I do not know whether other implementations has such optimization.