left_justify should still truncate the total length of the field

Commit cc69beb7091177933794fa65e097caf62d97df0e changed the implementation of left_justify to use ruby's ljust method on string.
But ljust doesn't truncate the string if it's length is greater.  Unless I'm missing something, I think this still needs to be added.

We saw this manifest as a bug in production with customer names that were longer than 22 characters after upgrading.
version bump
Merge pull request #15 from barmstrong/master

left_justify should still truncate the total length of the field