De/Serialization for wavefront object files

Adds to export/import topology as wavefront object files. This enables users to view/edit/use topology inside 3rd party 3D editors

ff/WavefrontSerializer.cpp

@@ -2,7 +2,7 @@
 //
 //  BornAgain: simulate and fit reflection and scattering
 //
-//! @file      ff/WavefronSerializer.cpp
+//! @file      ff/WavefrontSerializer.cpp
 //! @brief     Implements serialization and deserialization for polyhedra.
 //!
 //! @homepage  https://jugit.fz-juelich.de/mlz/libformfactor
@@ -16,23 +16,21 @@
 #include <fstream>
 #include <iomanip>
 #include <iostream>
+
 namespace {
 
 std::ostream& serialize_as_wavefront(std::ostream& out, const ff::Polyhedron* polyhedron)
 {
     out << std::setprecision(10);
-    out << "o 1"
-        << "\n";
+    out << "o 1 \n";
     for (auto vertice : polyhedron->vertices())
-        out << "v"
-            << " " << vertice.x() << " " << vertice.y() << " " << vertice.z() << "\n";
+        out << "v " << vertice.x() << " " << vertice.y() << " " << vertice.z() << "\n";
     out << "usemtl Default\n";
 
     for (auto& poly : polyhedron->topology().faces) {
         if (poly.vertexIndices.size() == 0)
             continue;
-        out << "f"
-            << " ";
+        out << "f ";
         for (size_t i = 0; i < poly.vertexIndices.size(); i++) {
             out << poly.vertexIndices[i] + 1;
             out << (i == poly.vertexIndices.size() - 1 ? "\n" : " ");
@@ -40,6 +38,7 @@ std::ostream& serialize_as_wavefront(std::ostream& out, const ff::Polyhedron* po
     }
     return out;
 }
+
 std::istream& deserialize_from_wavefront(std::istream& is, ff::Polyhedron*& polyhedron)
 {
     std::vector<R3> vertices;