* mark string as html safe before passing to translation instead of bypassing HTML escape using {{{unsafe}}} syntax
* replace ember-i18n with ember-intl
UX in browser which does not support time input type should be okay know by
validation messages and placeholder. Wasn't even used anymore in latest release.
Affects #90 but does not resolve 'unsafe-inline' requirement cause to
ember-bootstrap (https://github.com/kaliber5/ember-bootstrap/pull/98#discussion_r66586065).
* upgraded ember-moment and use it application-wide service to set locale
* label on poll/participation now observes locale changes, but it's still hacky
* replace computed property on views poll by moment-format helper of ember-moment
