feat: add exact mesh/material/texture hash and equal_to

LibCmo/LibCmo/CK2/ObjImpls/CKTexture.cpp

@@ -343,6 +343,10 @@ namespace LibCmo::CK2::ObjImpls {
 		return m_ImageHost;
 	}
 
+	const CKBitmapData& CKTexture::GetUnderlyingData() const {
+		return m_ImageHost;
+	}
+
 	bool CKTexture::LoadImage(CKSTRING filename, CKDWORD slot) {
 		// check file name
 		if (filename == nullptr) return false;

LibCmo/LibCmo/CK2/ObjImpls/CKTexture.hpp

@@ -20,6 +20,7 @@ namespace LibCmo::CK2::ObjImpls {
 		virtual bool Load(CKStateChunk* chunk, CKFileVisitor* file) override;
 
 		CKBitmapData& GetUnderlyingData();
+		const CKBitmapData& GetUnderlyingData() const;
 
 		/**
 		 * @brief A wrapper of underlying CKBitmapData::LoadImage. Not only load image, but also set file name.