Debugger: Implement remainder of #12729.

UserInterfaceListener:
- Add request hook for writing a core file. Implement in TeamDebugger.

Jobs/WriteCoreFileJob:
- Add new job to actually dispatch the core file request via the debugger
  interface.

Team{::Listener}
- Add listener event + hook for notifications when a core file gets written.
  Implement in CLI.

CliContext:
- Add event flag for core file changed.

CommandLineUserInterface:
- Add 'write-core' command. This optionally takes a path to write the core to,
  otherwise one is automatically generated by, similarly to debug reports. As
  such, one can now generate cores for things like app_server and registrar
  crashes if desired, in addition to reports.

src/apps/debugger/user_interface/cli/CommandLineUserInterface.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2015, Rene Gollent, [email protected].
+ * Copyright 2011-2016, Rene Gollent, [email protected].
  * Copyright 2012, Ingo Weinhold, [email protected].
  * Distributed under the terms of the MIT License.
  */
@@ -28,6 +28,7 @@
 #include "CliThreadCommand.h"
 #include "CliThreadsCommand.h"
 #include "CliVariablesCommand.h"
+#include "CliWriteCoreFileCommand.h"
 
 
 static const char* kDebuggerPrompt = "debugger> ";
@@ -311,7 +312,9 @@ CommandLineUserInterface::_RegisterCommands()
 		&& _RegisterCommand("thread", new(std::nothrow) CliThreadCommand)
 		&& _RegisterCommand("threads", new(std::nothrow) CliThreadsCommand)
 		&& _RegisterCommand("variables",
-			new(std::nothrow) CliVariablesCommand)) {
+			new(std::nothrow) CliVariablesCommand)
+		&& _RegisterCommand("write-core",
+			new(std::nothrow) CliWriteCoreFileCommand)) {
 		fCommands.SortItems(&_CompareCommandEntries);
 		return B_OK;
 	}