Modify top-level/extension property hierarchy

- rename KTopLevelProperty to KTopLevelVariable
- create KTopLevelExtensionProperty, a subclass of KExtensionProperty
- create KTopLevelProperty, a superclass of KTopLevelVariable and
  KTopLevelExtensionProperty. (In the future, it will have a container of type
  KPackage.)

core/reflection/src/kotlin/reflect/KTopLevelExtensionProperty.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.reflect
+
+public trait KTopLevelExtensionProperty<T, out R> : KExtensionProperty<T, R>, KTopLevelProperty<R>
+
+public trait KMutableTopLevelExtensionProperty<T, out R> : KTopLevelExtensionProperty<T, R>, KMutableExtensionProperty<T, R>, KMutableTopLevelProperty<R>

core/reflection/src/kotlin/reflect/KTopLevelProperty.kt

@@ -16,6 +16,6 @@
 
 package kotlin.reflect
 
-public trait KTopLevelProperty<out R> : KVariable<R>
+public trait KTopLevelProperty<out R> : KProperty<R>
 
-public trait KMutableTopLevelProperty<R> : KTopLevelProperty<R>, KMutableVariable<R>
+public trait KMutableTopLevelProperty<R> : KTopLevelProperty<R>, KMutableProperty<R>

core/reflection/src/kotlin/reflect/KTopLevelVariable.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.reflect
+
+public trait KTopLevelVariable<out R> : KVariable<R>, KTopLevelProperty<R>
+
+public trait KMutableTopLevelVariable<R> : KTopLevelVariable<R>, KMutableVariable<R>, KMutableTopLevelProperty<R>