Corrupt .public_name_cache

[dxdc]

Somehow, I found out my public_name_cache file became corrupt with a lot of binary junk at the beginning of it. This could be due to some force-quit operations I had to do (see #319).

During my troubleshooting, I realized there were multiple duplicate entries in this file and found the cause. The file was binary so grep was failing.

Wondering, what about running:

file -b --mime-type .public_name_cache to ensure it is a text file, and if not, save it to a backup and create a new one? Or, just strip any binary out of it using sed/another utility first?