2.5.0

• added ISO 3166-2 codes; see #61; thanks to Alan Jones for providing the links; what we have at this point should be considered as a start - a lot of codes are missing (according to Wikipedia which says there are 5047 while our list has only 3607) and names are written in their anglicized version rather than local - this will have to be updated by the community
• added Esperanto language
• updated formatting and usage of PHP files; thanks to Jacek Karczmarczyk for suggesting - see #58