Fix for translating dynamic enumeration values containing periods

Hi @cfitz

In migrating some Yale enumerations, we discovered that some codes containing periods.  Unfortunately, Rails uses periods as the separator for internationalisation codes and these failed to resolve correctly for any codes containing extra periods. 

The first commit patches this issue and will allow users to add periods in their enumeration values and these translated values will now display correctly in the form dropdown list/combobox.

The second patch fixes an issue with the combobox widget.  We noticed that the typeahead list would close if the scrollbar was mouse-clicked.. rendering it unusable for mouse users.

Thanks!