Compilation error in 'ply_io.cpp' with clang 3.5.0

I am able to compile pcl trunk with `gcc`, however when I switch to `clang` (version 3.5.0) I get the following errors:

    /media/Workspace/Libraries/pcl/io/src/ply_io.cpp:534:17: error: no member named 'at' in namespace 'pcl::io::ply'
      pcl::io::ply::at<pcl::io::ply::float64> (scalar_property_definition_callbacks) = boost::bind (&pcl::PLYReader::scalarPropertyDefinitionCallback<pcl::io::ply::float64>, this, _1, _2);
      ~~~~~~~~~~~~~~^
    /media/Workspace/Libraries/pcl/io/src/ply_io.cpp:534:41: error: expected '(' for function-style cast or type construction
      pcl::io::ply::at<pcl::io::ply::float64> (scalar_property_definition_callbacks) = boost::bind (&pcl::PLYReader::scalarPropertyDefinitionCallback<pcl::io::ply::float64>, this, _1, _2);
      ~~~~~~~~~~~~~~~~~~~~~^

And similar ones for lines 535 through 553.

Indeed, I also can not find `at` function in `pcl::io::ply` namespace. There is `at` function in `pcl::io::ply::ply_parser` though.

@nizar-sallem I see you are listed in the authors. Any ideas about this?