Refactor + Bugs fixes on Strings + Gestion de la génération des images

SampleFiles/Images/imagium.xcassets/welcome_background.imageset/Contents.json

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x",
+      "filename" : "welcome_background.png"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x",
+      "filename" : "welcome_background@2x.png"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x",
+      "filename" : "welcome_background@3x.png"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "ResgenSwift-Imagium"
+  }
+}