message: Implement getBatchSize for Intel's Inference Engine networks
diff: @@ -331,8 +331,18 @@ InferenceEngine::StatusCode InfEngineBackendNet::setBatchSize(size_t size, Infer
  size_t InfEngineBackendNet::getBatchSize() const noexcept
  {
  - CV_Error(Error::StsNotImplemented, "");
  - return 0;
  + size_t batchSize = 0;
  + for (const auto& inp : inputs)
  + {
  + CV_Assert(inp.second);
  + std::vector<size_t> dims = inp.second->getDims();
  + CV_Assert(!dims.empty());
  + if (batchSize != 0)
  + CV_Assert(batchSize == dims.back());
  + else
  + batchSize = dims.back();
  + }
  + return batchSize;
  }
  #if INF_ENGINE_VER_MAJOR_GT(INF_ENGINE_RELEASE_2018R2)
  