Fix the end of the replaced identifier for completion with tab char

Stop removing (, ), {, }, + and so on.
Update ReadMe.md to reflect changes in the bootstrapping configuration
Fix references in ReadMe.md
fixed bug

NULL_FOR_NONNULL_TYPE can represent type mismatch error as well
(later the whole method 'makeTraceInterceptingTypeMismatch' should be removed)
test added
removed ConstraintSystemWIthPriorities
refactoring: extracted methods
extracted ConstraintSystemStatus
refactoring: moved 'getValue', 'getValues' methods to TypeConstraints
refactoring: moved methods
KT-3573 "Error generating primary constructor" when trying to use "this" in extensions from constructors

  #KT-3573 Fixed
Obtaining jflex from github. No IDEA checkout is necessary anymore.
Removed IDE templates support from plugin.
Removed IDE templates support from compiler.
Removed IDE templates from completion, replaced them with keywords.
Minor. Using more common class.
Made parsing test generated.
Generated missing test data.
Changed extension in parsing test data (jet -> kt)
Show IncorrectSourceRootName notification for gradle project also