Use new format for RailsAdmin rich text editors.

They have been separated out into separate fields, and the old config
variables are deprecated.

See https://github.com/sferik/rails_admin/commit/967efc6f875c5f2075c697e22e894cad2fbc99b1
Remove satisfy_strong_params! to make compatible with latest RailsAdmin

See https://github.com/sferik/rails_admin/commit/d2db06c413b0b709ddddcf47594a49fc46deaa44
Use Globalize instead of I18n for translating globalize fields
Merge pull request #10 from benhutton/compatibility-fixes

Compatibility fixes