Formatting floating point numbers don't allocate with the GC anymore.

The implementation of formatting floating point numbers has been
reworked. We made sure that working examples never allocate with the
GC, however, we are still using exceptions which are GC managed.
Therefore, code that uses formatting correctly will never allocate,
but in the case of exceptions, the GC will be used to allocate the
exception. We are working on DIP 1008 to solve this issue.
