String Theory 2.1

• Fix major bug in ST::buffer<T>::operator==() and ST::buffer<T>::allocate(size, fill) for types of T larger than char.
• Fix ST::string_stream::operator<<() for float and double not actually writing the value to the stream.
• Fix potential undefined behavior formatting -(MAX_*) integers.
• Add more unit tests for the fixed cases and others.
• Slight performance improvement for simple integer formatters.
• Guarantee case insensitive conversions and comparisons occur in the "C" locale.
• Remove <cstring> include from public headers.