disable brush pressure averaging, implement single finger for camera rotation when touch draw is disabled

src/canvas_modes.cpp

@@ -16,8 +16,20 @@ void CanvasModeBasicCamera::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
     switch (me->m_type)
     {
         case kEventType::MouseDownL:
+            if (canvas->m_touch_lock && me->m_source == kEventSource::Touch)
+            {
+                m_draggingR = true;
+                m_dragR_start = me->m_pos;
+                m_pan_start = canvas->m_pan;
+                node->mouse_capture();
+            }
             break;
         case kEventType::MouseUpL:
+            if (canvas->m_touch_lock && me->m_source == kEventSource::Touch)
+            {
+                m_draggingR = false;
+                node->mouse_release();
+            }
             break;
         case kEventType::MouseDownR:
             if (App::I.keys[(int)kKey::KeyAlt])