Building-Netgen.md

+```
+cmake \
+-DCMAKE_BUILD_TYPE=Release \
+-DUSE_OCC=ON \
+-DUSE_SUPERBUILD=OFF \
+-DUSE_GUI=ON \
+-DUSE_CCACHE=OFF \
+-DUSE_PYTHON=OFF \
+-DCMAKE_INSTALL_PREFIX="/usr/local" \
+../..
+```
\ No newline at end of file