Improve support for C++98 compilers that require a copy ctor when binding a reference to a temporary.

Add support for long long and more tests for unsigned long long. https://github.com/vitaut/format/issues/9

Remove IntTraits<uint32_t> because uint32_t is a typedef, not a built-in type. Rename ULLONG to ULONG_LONG for consistency with ulong_long_value. Remove extra whitespace.

Want to be able to format the following without any casting

std::cout << fmt::str(fmt::Format("{:x}") << 0xAEull) << std::endl;
std::cout << fmt::str(fmt::Format("{:x}") << 0xAEul) << std::endl;
std::cout << fmt::str(fmt::Format("{:x}") << uint64_t(0xae)) <<
std::endl;

Document the 'B' type and the difference between 'b' & 'B'. Addresses part of issue https://github.com/vitaut/format/issues/5

Document that "#x" adds prefix "0x" and "#X" adds "0X". Addresses part of issue https://github.com/vitaut/format/issues/5