Don't output 1000 kB for 1.0 MB

[pjakubik]

When the bytes round up to 1.0 of the next higher unit, humanize.Bytes will produce strings like 1000 kB or 1024 KiB instead of 1.0 MB or 1.0 MiB.

I will submit a pull request with a fix.

[pjakubik]

fix.tgz

I don't have permissions to push a branch to create a pull request, so I've attached a tar.gz file with the modified files. Let me know if you need a different archive format for the fixes.

[pjakubik]

The code in fix.tgz also fixes issue #103 and replaces the Sprintf calls with more efficient formatting so that after fixing humanizeBytes and humanizeBigBytes are faster than before they were fixed.

[pjakubik]

I learned how to make pull requests for open source projects and created pull request #128 with fixes.