Update ru_RU.lang and fixed Yak-9's decal

Updated ru_RU, added Pak-40 to en_US.lang.
Fixed Yak-9's decal: before - http://puu.sh/aXEaI/58ac5d70e4.jpg, after
- http://puu.sh/aXEmc/5436d0c05d.jpg (now 'МОД' is more like 'МОД' and
less like 'МОА')
Merge pull request #440 from NitroBoy2/dev

Updated ru_RU.lang and fixed Yak-9's decal