-Wtautological-constant-out-of-range-compare

When ConverterImpl was instantiated with a large enough integer type, a comparison to make sure a std::size_t wasn't bigger than the maximum value of that type was triggering a warning -- -Wtautological-constant-out-of-range-compare -- in Clang.

This check doesn't accomplish much, and therefore was removed.
Floating Point Conversion Fixes

Fixed various floating point conversion bugs which caused erroneous successes, including:

- Conversion of the empty string to zero
- Conversion of strings with extra decimal places to numeric values obtained by simply disregarding the erroneous decimal place(s) and everything thereafter (i.e. "1.1.1" => 1.1)
- Conversion of strings with leading/trailing white space