Added errors annotation. Available only on compilation unit.
Changes for adding error message to AST. Changed the way to specify java
version to the compiler from a method to a keyword parameter.
Removed the setJavaVersion method and related code.
Fixed exception caused by empty java file.
Fixed the mistake with length check.
Added new relations.
Changes for extracting the new relations.
Added initializer binding and changed handling of anonymous classes to
tie them with their parent.