Make various updates and fixes (#198)

csrc/jit_kernels/impls/epilogue.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <optional>
+#include <string>
+
+namespace deep_gemm {
+
+static std::string get_default_epilogue_type(const std::optional<std::string>& epilogue_type) {
+    return epilogue_type.value_or("EpilogueIdentity");
+}
+
+} // namespace deep_gemm