Introduce InlineClasses language feature

Allow to write `inline` modifier in front of class declaration

compiler/serialization/src/org/jetbrains/kotlin/serialization/DescriptorSerializer.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 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.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.serialization
@@ -73,7 +62,7 @@ class DescriptorSerializer private constructor(
         val flags = Flags.getClassFlags(
                 hasAnnotations(classDescriptor), normalizeVisibility(classDescriptor), classDescriptor.modality, classDescriptor.kind,
                 classDescriptor.isInner, classDescriptor.isCompanionObject, classDescriptor.isData, classDescriptor.isExternal,
-                classDescriptor.isExpect
+                classDescriptor.isExpect, classDescriptor.isInline
         )
         if (flags != builder.flags) {
             builder.flags = flags