Removed signal handlers from draw3

+ caused deadlocks on program exit, as functions called from signal handler were not async-signal-safe (see: man signal-safety). Amongst others, malloc and pthread_join are not safe.
+ OS will cleanup our threads and db queue anyway
+ saving defined user params on exit is no longer necessary as we save them on every edit action
+ because of all the above, we can safely leave signal handling and cleanup to standard OS behavior on Linux

wx/draw3/drawapp.cpp

@@ -151,12 +151,6 @@ extern void InitXmlResource();
 bool read_only;
 std::unique_ptr<FileLocker> m_instance;
 
-void handler(int sig)
-{
-	wxGetApp().OnExit();
-	_exit(0);
-}
-
 namespace {
 int GL_ATTRIBUTES[] = {
 	WX_GL_RGBA,
@@ -241,9 +235,6 @@ bool DrawApp::OnInit() {
 
 
 	SetProgName(_T("Draw 3"));
-	signal(SIGHUP, handler);
-	signal(SIGINT, handler);
-	signal(SIGTERM, handler);
 
 	if (m_just_print_version) {
 		std::cout << SZARP_VERSION << std::endl;

wx/draw3/include/drawapp.h

@@ -96,7 +96,7 @@ class DrawApp : public DrawGLApp
 {
 public:
 	/** 
-	 * Method called on application end and on sigint.
+	 * Method called on application end.
 	 */
 	int OnExit();