Merge branch 'release/0.12'

Conflicts:
    locale/he_IL/app.po
    locale/hr_HR/app.po
    locale/nb_NO/app.po
    locale/uk/app.po
Backport https://github.com/mikel/mail/pull/405 to prevent stack overflow errors when parsing large mails with envelopes on memory limited systems.
Merge branch 'hotfix/0.12.0.1' into rails-3-develop

Conflicts:
    locale/he_IL/app.po
    locale/nb_NO/app.po