windows: add console input api

[aymanbagabas]

This adds multiple functions to read, count, and discard console input events. Using ReadConsoleInput instead of ReadConsole or ReadFile is necessary to capture extended events such as window resize, focus, and extended key and mouse events.

This also define console event types and structs.

[gopherbot]

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[gopherbot]

Message from Gopher Robot:

Patch Set 1:

(1 comment)

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[gopherbot]

Message from Ayman Bagabas:

Patch Set 1:

(1 comment)

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Please don’t reply on this GitHub thread. Visit golang.org/cl/621515.
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