Fix #1938: Debuggee output is UTF-8 regardless of locale

Fix #1954: "redirectOutput" property is not respected

If "redirectOutput" is specified, always capture output as UTF-8, and encode it according to locale and Python settings.

Change the default for "redirectOutput" to be false when "console" is not set to "internalConsole", to minimize differences in behavior when running under debugger for most common scenarios.

Refactor ptvsd.launcher package to minimize circular dependencies between modules.

.vscode/launch.json

@@ -25,8 +25,8 @@
             "console": "integratedTerminal",
             //"console": "externalTerminal",
             "consoleTitle": "ptvsd.server",
-            //"program": "${file}",
-            "program": "${workspaceFolder}/tests/test_data/testpkgs/pkg1/__main__.py",
+            "program": "${file}",
+            "logToFile": true,
         },
         {
             "name": "Attach [debugServer]",
@@ -34,6 +34,7 @@
             "request": "attach",
             "host": "localhost",
             "port": 5678,
+            "logToFile": true,
         },
     ]
 }