fix deserialization for dtkMatrix
fix deserialization for dtkMatrix

NicolasSchnitzler/dtk,NicolasSchnitzler/dtk,d-tk/dtk,NicolasSchnitzler/dtk,rdebroiz/dtk,rdebroiz/dtk,d-tk/dtk,rdebroiz/dtk,d-tk/dtk,d-tk/dtk,NicolasSchnitzler/dtk,rdebroiz/dtk,d-tk/dtk,d-tk/dtk