Refactor type casting in Cython files for improved clarity and consistency

- Updated various Cython files to explicitly cast types, enhancing type safety and readability.
- Adjusted the `engine_name` property in `InferenceEngine` and its subclasses to be set directly in the constructor.
- Modified the `request` method in `_SessionWithBase` to accept `*args` for better flexibility.
- Ensured proper type casting for return values in methods across multiple classes, including `Inference`, `CoreMLEngine`, and `TensorRTEngine`.

These changes aim to streamline the codebase and improve maintainability by enforcing consistent type usage.

run-tests.sh

@@ -17,6 +17,9 @@ cleanup() {
 }
 trap cleanup EXIT
 
+echo "Building Cython extensions ..."
+python setup.py build_ext --inplace
+
 for port in $LOADER_PORT $ANNOTATIONS_PORT $DETECTIONS_PORT; do
     if lsof -ti :"$port" >/dev/null 2>&1; then
         echo "ERROR: port $port is already in use" >&2