Fixed two more locales-related issues

One warning was also fixed

src/libslic3r/AppConfig.hpp

@@ -178,7 +178,7 @@ private:
 	    auto it_val = it->second.find(parameter_name);
 	    if (it_val == it->second.end())
 	        return false;
-	    out = T(::atof(it_val->second.c_str()));
+        out = T(string_to_double_decimal_point(it_val->second));
 	    return true;
 	}
 

src/libslic3r/Geometry.cpp

@@ -1494,6 +1494,7 @@ Transformation Transformation::volume_to_bed_transformation(const Transformation
 // For parsing a transformation matrix from 3MF / AMF.
 Transform3d transform3d_from_string(const std::string& transform_str)
 {
+    assert(is_decimal_separator_point()); // for atof
     Transform3d transform = Transform3d::Identity();
 
     if (!transform_str.empty())