Issue Description

The code inside pipeline::start methods (overloads accepting callback) is dangerous and could be a potential source of memory leak:

        template<class S>
        pipeline_profile start(const config& config, S callback)
        {
            rs2_error* e = nullptr;
            auto p = std::shared_ptr<rs2_pipeline_profile>(
                rs2_pipeline_start_with_config_and_callback_cpp(_pipeline.get(), config.get().get(), new frame_callback<S>(callback), &e),
                rs2_delete_pipeline_profile);

            error::handle(e);
            return pipeline_profile(p);
        }

Problem statement:
The ownership of the memory allocated for the frame_callback object is passed to rs2_pipeline_start_with_callback_cpp function however there are control flows where the memory will not be properly released:

• argument evaluation order is unspecified and config.get() may throw an exception while memory is already allocated
• there is a case inside the rs2_pipeline_start_with_config_and_callback_cpp implementation when an exception may happen before ownership of the passed memory is accepted.