fix #1456: crash when running iso parametrization: main on low resolution meshes

Author: alemuntoni

.devcontainer/Dockerfile

@@ -17,6 +17,7 @@ RUN apt-get -y update && DEBIAN_FRONTEND=noninteractive apt-get -y install \
     dbus-x11 \
     fontconfig \
     fuse \
+    gdb \
     git \
     kmod \
     libboost-dev \

src/meshlabplugins/filter_isoparametrization/parametrizator.h

@@ -599,6 +599,8 @@ class IsoParametrizator{
     ///set the best value considering the ratio value
     bool SetBestStatus(bool test_interpolation)
     {
+        if (ParaStack.size() == 0)
+            return false;
         std::sort(ParaStack.begin(),ParaStack.end());
         int indexmin=0;
         bool isOK_interp;