.travis.yml: add Python 3.4.

According to https://github.com/travis-ci/travis-ci/issues/1989 Travis
will get Python versions from
https://launchpad.net/~fkrull/+archive/deadsnakes
and that PPA has python3.4 so it should be installed to them soon.

Feel free to not merge this until it has happened.
Merge pull request #590 from Mkaysi/travis

.travis.yml: add Python 3.4.
Revert ".travis.yml: add Python 3.4."

This reverts commit d84f6b48344bce0c3f225d8d695680ae86bb6ff6.
Add 'reply_env' attribute to IrcMsg.
Copy the reply_env when copying an IrcMsg object.
Fix previous commit.