Dev/stuff from pyctbgui (#273)

Matterhorn10 Transform 
some other Transformations from pyctbGUI 
added method get_reading_mode for easier error handling in decoders 


## TODO: 

- proper error handling for all other decoders 
- proper documentation for all other decoders 
- refactoring all other decoders to store hard coded values in a Struct
ChipSpecification

src/decode.test.cpp

@@ -152,4 +152,24 @@ TEST_CASE("Expand container with 24 bit data to 32") {
         CHECK(out(1) == 0xFFF);
         CHECK(out(2) == 0xFF0);
     }
+}
+
+TEST_CASE("Expand 4 bit values packed into 8 bit to 8 bit values") {
+    {
+        uint8_t buffer[] = {
+            0x00, 0xF0, 0xFF, 0x00, 0xF0, 0xFF,
+        };
+
+        aare::NDView<uint8_t, 1> input(&buffer[0], {6});
+        aare::NDArray<uint8_t, 1> out({12});
+        aare::expand4to8bit(input, out.view());
+
+        uint8_t expected_output[] = {
+            0x0, 0x0, 0x0, 0xF, 0xF, 0xF,
+            0x0, 0x0, 0x0, 0xF, 0xF, 0xF}; // assuming little endian
+
+        for (size_t i = 0; i < 12; ++i) {
+            CHECK(out(i) == expected_output[i]);
+        }
+    }
 }