Added a unicode example.

Note: Because there's no standard unicode locale, this depends on the
user's locale.  Consequently, this may not work for all users (likely
people who don't have other unicode working correctly, either).
Moreover, I cannot guarantee adequate glyph coverage for the charaters
used; the current example string is mixed first-level Japanese and ASCII.
simple_spectrum: Samples of 256-colour wncurses output in D.

Extended colour support was added in ncurses 5.5 for the wncurses
library.
simple_spectrum: added more documentation comments
simple_spectrum: whitespace cleanup because I use tabs and others don't.
hello_unicode: Added notes for getting correct output

Unicode is slightly complicated and I neglected to document this.
Merge pull request #2 from Wyatts/master

Add a unicode example.