aiorepl: Use stdin in binary mode and catch windows enter presses

[sandyscott]

Changed this to use stdin.buffer instead of stdin. Now catches and ignores the consecutive line ending characters within 20ms of the previous.

[dlech]

Changed this to use stdin.buffer instead of stdin.

Is this going to cause problems with multi-byte unicode characters since it now reads one byte instead of one unicode character?

[sandyscott]

Having thought about this a bit more, this is going to get messy fast. The aiorepl server would need knowledge of the terminal's character encoding to properly decode the characters. UTF-8 is not a safe assumption: if the terminal is using an 8-bit character set and sends any single-byte character above 0xBF this could cause the server to hang while it waits for the second byte that will never come. The code would also need a fairly significant restructure to separate the decoding from the actions. I think the simpler fix in #560 is a safer way to fix the specific issue I encountered - that windows line endings are interpreted as two presses of the enter key.