CLI: change "-suppress warnings" option to "-nowarn"

Following the rule of the least surprise: this option is named "-nowarn" in
other JVM language compilers. Besides, having an option with an argument which
can take exactly one predefined value is sort of confusing

compiler/cli/cli-common/src/org/jetbrains/jet/cli/common/arguments/CommonArgumentConstants.java

@@ -1,21 +0,0 @@
-/*
- * Copyright 2010-2013 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 org.jetbrains.jet.cli.common.arguments;
-
-public interface CommonArgumentConstants {
-    String SUPPRESS_WARNINGS = "warnings";
-}

compiler/cli/cli-common/src/org/jetbrains/jet/cli/common/arguments/CommonCompilerArguments.java

@@ -22,9 +22,10 @@ import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
 
-import static org.jetbrains.jet.cli.common.arguments.CommonArgumentConstants.SUPPRESS_WARNINGS;
-
 public abstract class CommonCompilerArguments {
+    @Argument(value = "nowarn", description = "Generate no warnings")
+    public boolean suppressWarnings;
+
     @Argument(value = "tags", description = "Demarcate each compilation message (error, warning, etc) with an open and close tag")
     public boolean tags;
 
@@ -37,19 +38,11 @@ public abstract class CommonCompilerArguments {
     @Argument(value = "help", alias = "h", description = "Print a synopsis of standard options")
     public boolean help;
 
-    @Argument(value = "suppress", description = "Suppress all compiler warnings")
-    @ValueDescription(SUPPRESS_WARNINGS)
-    public String suppress;
-
     @Argument(value = "X", description = "Print a synopsis of advanced options")
     public boolean extraHelp;
 
     public List<String> freeArgs = new SmartList<String>();
 
-    public boolean suppressAllWarnings() {
-        return SUPPRESS_WARNINGS.equalsIgnoreCase(suppress);
-    }
-
     @NotNull
     public String executableScriptFileName() {
         return "kotlinc";

compiler/cli/src/org/jetbrains/jet/cli/common/CLICompiler.java

@@ -109,7 +109,7 @@ public abstract class CLICompiler<A extends CommonCompilerArguments> {
 
         MessageCollector collector = new PrintingMessageCollector(errStream, messageRenderer, arguments.verbose);
 
-        if (arguments.suppressAllWarnings()) {
+        if (arguments.suppressWarnings) {
             collector = new FilteringMessageCollector(collector, Predicates.equalTo(CompilerMessageSeverity.WARNING));
         }