[WIP] check integer number range in vistor 

hi @Alefas, I think it's a better version now. could you go through it?
Also I cannot get the test running for now, test cases will be later.
We can check language level and report error if it's >= 2.11.
import org.jetbrains.plugins.scala.project package object.
Then on psi element invoke languageLevel, which returns option.