Enchancments

[NEW]
* Russian translation
* Allow to use with custom API Key

[BUGS]
1) Guys, I'm stupid git user, so, not everything is perfect with commits, f.ex commit N1 is almost the same is N3 and N2 reverts N1, I can't delete them, sorry. You only need N3 (31a7206), look carefully, I could mistaken somewhere.
2) There're some new Gradle files. I don't know what to do with them. I hate this f**king Android Studio and this f**king Gradle :(
3) Something strange with onClickListener. I can't make textviews with result link clickable. Tried many things, don't work. Could you look into it? 
4) I've edited upload rules and moved your api key to constant for easier editing for you.

[TODO]
1) Maybe I manage to implement onClick (if Error instead of link in TextView, Alert is shown and app do not crash)
2) Select paste language from dropdown list