Resolves #14

This adds some simple logic to check for basic quoting of the email subject, and strip it out if it's being used.  RFC2047 quoting using =?charset?encoding?encoded-text?= won't be affected, but simple quoting using " characters will be stripped from email subjects.
Merge pull request #15 from nelsam/simple-quoted-subjects-fix

Strip basic quoting from email subjects - resolves #14