Introduce Chars

This improves the implementation by introducing a class to manage the characters

docker/Dockerfile

@@ -4,8 +4,7 @@ USER root
 
 RUN python -m pip install --upgrade \
     pip \
-    -i https://test.pypi.org/simple/  \
-        ilp-keyboard-layout-optimization
+    ilp-keyboard-layout-optimization
 
 USER user
 
@@ -14,9 +13,7 @@ FROM optimizer as tester
 USER root
 
 RUN python -m pip install --upgrade \
-    pip \
-    -i https://test.pypi.org/simple/  \
-        ilp-keyboard-layout-optimization[test]
+    ilp-keyboard-layout-optimization[test]
 
 USER user