all: don't re-code twice before outputting with WriteConsoleW()

Otherwise characters that are not present in the local charset are
lost. Fixes #971.
all: use UTF-8 by default for --redirect-output on Windows
all: Windows: set binary mode on STDOUT for the console

Prevents the C library from turning \n written to the console (stdout)
to be turned into \r\n as MKVToolNix' common library does that
already. Fixes #970.
docs: update man pages regarding character set conversions/console charset
Merge branch 'windows-console-charset'