Imported Upstream version 30.0~b1
Merge tag 'upstream/30.0_b1'

Upstream version 30.0~b1

# gpg: Unterschrift vom Mo 09 Jun 2014 15:45:33 EDT mittels RSA-Schlüssel ID A74420EF
# gpg: Korrekte Unterschrift von "Christoph Goehre <christoph.goehre@gmx.de>"
# gpg:                     alias "Christoph Goehre <chris@sigxcpu.org>"
rebuild patch queue from patch-queue branch
debian/changelog: update copyright to MPL-2.0

Like in Firefox Mozilla was updating the copyright license for
Thunderbird as well, to respect the upstream changes which comes since
version 23 we rework the copyright information for the upstream sources.
adjust icedove depends >= 30.0~ and icedove << 31
document changes and release 1:30.0~b1-1