Bump version 3.3 -> 3.4
Remove package version from source code

It was a pain to update, and not needed any longer, see this quote my
@milkypostman:

    MELPA generates a version number based on the last commit date to
    any relevant file. Melpa-stable uses the version from the tag. It's
    up to you if you update the version number but when you gave a
    version it's probably proper form to still change the version number
    for those who may download the actual zip package manually outside
    of MELPA.

    https://github.com/milkypostman/melpa/pull/2220#issuecomment-64948213