UTF-8 support #8
Description
When strings are created, detect UTF-8 and store them as UCS-4. Storing them as code point values will make dealing with them easier, processing will be faster (conversions are done on the way in), at the cost of some memory usage (I'm assuming strings will be mostly ASCII anyway). This will require no significant changes to the code (SIMD or scalar) except switching to wider integer types when necessary.