KT-3250 Copyright plugin does not work on Kotlin sources
New package 'versions' created
AbiVersionIndex added
Common library-related logic is extracted from UI classes to a util class
Assert message
Handle non-existent files
Assertion message
Library created under write action
Finding library roots with wrong ABI versions
A method to find local VirtualFile for Kotlin runtime library
Continuation added to updateRuntime()
Notifications about unsupported ABI versions
Version-related classes moved to the appropriate package
Class renamed
Subscribe for exitDumbMode() to update notifications

Instead of scheduling runWhenSmart(), which does not work sometimes
Look up kotlin-runtime.jar through the marker class + more marker classes
Remove codegen tests out of JetNpeTest
Sort out blackBox*() methods

- get rid of blackBox(), extract tests into files
- delete single-file usages of blackBoxMultiFile()
- inline some other blackBox methods
- suppress exception in blackBoxWithJava()
Refactor CodegenTestCase

- prohibit main(Array<String>) in favor of box(): String
- move all script-related code to ScriptGenTest
- remove unused environment-creating methods
- inline trivial methods & other minor stuff
Codegen tests: don't generate twice when a test fails