partial support for 'abstract' modifier added

idea/testData/checker/ForRangeConventions.jet

@@ -4,65 +4,65 @@ class NotRange1() {
 
 }
 
-class NotRange2() {
-  fun iterator() : Unit
+abstract class NotRange2() {
+  abstract fun iterator() : Unit
 }
 
-class ImproperIterator1 {
-  fun hasNext() : Boolean
+abstract class ImproperIterator1 {
+  abstract fun hasNext() : Boolean
 }
 
-class NotRange3() {
-  fun iterator() : ImproperIterator1
+abstract class NotRange3() {
+  abstract fun iterator() : ImproperIterator1
 }
 
-class ImproperIterator2 {
-  fun next() : Boolean
+abstract class ImproperIterator2 {
+  abstract fun next() : Boolean
 }
 
-class NotRange4() {
-  fun iterator() : ImproperIterator2
+abstract class NotRange4() {
+  abstract fun iterator() : ImproperIterator2
 }
 
-class ImproperIterator3 {
-  fun hasNext() : Int
-  fun next() : Int
+abstract class ImproperIterator3 {
+  abstract fun hasNext() : Int
+  abstract fun next() : Int
 }
 
-class NotRange5() {
-  fun iterator() : ImproperIterator3
+abstract class NotRange5() {
+  abstract fun iterator() : ImproperIterator3
 }
 
-class AmbiguousHasNextIterator {
-  fun hasNext() : Boolean
+abstract class AmbiguousHasNextIterator {
+  abstract fun hasNext() : Boolean
   val hasNext : Boolean get() = false
-  fun next() : Int
+  abstract fun next() : Int
 }
 
-class NotRange6() {
-  fun iterator() : AmbiguousHasNextIterator
+abstract class NotRange6() {
+  abstract fun iterator() : AmbiguousHasNextIterator
 }
 
-class ImproperIterator4 {
+abstract class ImproperIterator4 {
   val hasNext : Int get() = 1
-  fun next() : Int
+  abstract fun next() : Int
 }
 
-class NotRange7() {
-  fun iterator() : ImproperIterator3
+abstract class NotRange7() {
+  abstract fun iterator() : ImproperIterator3
 }
 
-class GoodIterator {
-  fun hasNext() : Boolean
-  fun next() : Int
+abstract class GoodIterator {
+  abstract fun hasNext() : Boolean
+  abstract fun next() : Int
 }
 
-class Range0() {
-  fun iterator() : GoodIterator
+abstract class Range0() {
+  abstract fun iterator() : GoodIterator
 }
 
-class Range1() {
-  fun iterator() : Iterator<Int>
+abstract class Range1() {
+  abstract fun iterator() : Iterator<Int>
 }
 
 fun test() {