updated Admin support for fields with 'preview' value
updated tip list with preview https://github.com/globaleaks/GlobaLeaks/issues/515
updated tip status page with context info: https://github.com/globaleaks/GlobaLeaks/issues/513
Merge pull request #87 from globaleaks/issue/515

Issue/515
Merge pull request #88 from globaleaks/issue/513

updated tip status page with context info: https://github.com/globaleaks...
Support also printing out optional error arguments
Merge pull request #89 from globaleaks/bugfix/524

Support also printing out optional error arguments
Merge branch 'master' into feature/extend_expire_date