Updating the license file to a SQLite 3 model.
Commit of string normalization.

* definition of basic_string<> types for Utf8, Ucs2, Utf16 and Ucs4 using char, char16_t and char32_t
* validation routines for all four formats with potential targets for all four as well as 7-bit ASCII and the Unicode range.
* conversion routines between all four formats, guaranteed to succeed iff C++ memory allocation succeeds and validation routines succeeded.
* conversion routines from CP-1250 and CP-1252 to UTF-8
* "string length" functions for UTF-8 and UTF-16 strings to give length (for valid strings) in Unicode code points
* unit tests for all routines in package