Replaced ASCII greater-than-or-equal-to with >= to resolve 'invalid multibyte char (US-ASCII)' error.

This is basically a reapplication of commit 41b5a6e50eb3b90768f5aac5403e9165162452d8, from https://github.com/ttscoff/Slogger/pull/54. It looks like the multibyte character was added back in commit f298e93b6399943ba51df901ed4626bab6257237.