STLplus C++ library collection SVN stlplus3

Tidy up and re-style banner

Separated from the std::string utilities - this is part of the basic types support

Moved and renamed from arithmetic - an extra general-purpose exception for
arithmetic operations

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Added inf to portability from arithmetic library which has been removed

Removed arithmetic library

Script for generating colourised listings

Tidied up and changed the banner style

Renamed containers_fixes

I've decided to scrap the arithmetic library - not big enough to justify a
whole library