windows: add VT100 codes ?25l and ?25h (hide/show cursor)

One of the first machines to support ANSI was the VT100; two of its extension codes, `?25l` and `?25h` (hide/show cursor, respectively) are still in use today (and are supported by most/all ANSI-compliant terminals).

This patch adds support for this in Windows using `Get`/`SetConsoleCursorInfo` and introduces a skipped character `?` to the ANSI parser.

> An initial `?` is innocuous to *any* escape sequence; this means this will not break if `CSI [?31m` is outputted; as expected, dark red text is shown.