[#21] Fix i18n calls

All the 'self' on the 'showError' function should be 'this', otherwise you
will refer to the window. Also 'this.i18n' assumes an 'i18n' key in the
module options. Looks like you are trying to pass some variables to the
string template, note the sprintf-like syntax.
[#21] Make popup table match the rest of CKAN tables