new activities:

• categorisation
• guesscount
• bargame
• bargame_2players
• checkers
• checkers_2players

misc:

• Polish lang dataset by Łukasz Wojniłowicz
• Swedish lang dataset by Stefan Asserhäll
• Ukrainian lang dataset by Yuri Chornoivan
• new icons
• updated graphics on several activities
• website translated in Belarusian, Catalan, Catalan (Valencia), Romanian, Portuguese and Ukrainian
• new mingw windows builds

todo:

• Update screenshots page with new activities.
• Update images for:
  • categorisation (at least the icon)
  • bargame, bargame_2players (everything?)