UTF8-CPP: UTF-8 with C++ in a Portable Way

Many C++ developers miss an easy and portable way of handling Unicode
encoded strings. The original C++ Standard (known as C++98 or C++03) is
Unicode agnostic. C++11 provides some support for Unicode on core
language and library level: u8, u, and U character and string literals,
char16_t and char32_t character types, u16string and u32string library
classes, and codecvt support for conversions between Unicode encoding
forms. In the meantime, developers use third party libraries like ICU,
OS specific capabilities, or simply roll out their own solutions.

In order to easily handle UTF-8 encoded Unicode strings, I came up with
a small generic library. For anybody used to work with STL algorithms
and iterators, it should be easy and natural to use. The code is freely
available for any purpose - check out the license at the beginning of
the utf8.h file. If you run into bugs or performance issues, please let
me know and I'll do my best to address them.