Windows platform support

[fbbdev]

This amounts to two changes:

• Support Windows Console API in terminal.hpp functions
• Implement Unicode console output through WriteConsoleW. This means switching to wstring and wostream, or setting up cout locale to convert UTF-8 to UTF-16 (with codecvt_utf8_utf16).

See:

• wostream fails to output wstring http://stackoverflow.com/questions/11610583/wostream-fails-to-output-wstring
• std::codecvt_utf8_utf16 http://en.cppreference.com/w/cpp/locale/codecvt_utf8_utf16

[fbbdev]

This still leaves the real question unanswered: will the Windows Console print out braille characters? 😕