fix #766 IE8 issue when displaying a popup.

This fix has two parts, firstly it will resolve an issue
for animations in IE8 when displaying a popup, and secondly
it refactors a bit the way animations are used, there is now
a getter to load animations when they are actually needed,
and not for all popups as was previously the case (this will
help to improve performance particularly for IE8).
fix #773 Wrong translation in FooterRes_pt_BR.js

Close #774