Added a FeistelManager to en/decipher arbitrarily long messages using cipher block chaining

Feistel.vcxproj.filters

@@ -24,6 +24,9 @@
     <ClCompile Include="main.cpp">
       <Filter>Quelldateien</Filter>
     </ClCompile>
+    <ClCompile Include="FeistelMan.cpp">
+      <Filter>Quelldateien</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Feistel.h">
@@ -44,5 +47,11 @@
     <ClInclude Include="Util.h">
       <Filter>Headerdateien</Filter>
     </ClInclude>
+    <ClInclude Include="FeistelMan.h">
+      <Filter>Headerdateien</Filter>
+    </ClInclude>
+    <ClInclude Include="Flexblock.h">
+      <Filter>Headerdateien</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>