docs: add missing descriptions

Author: robcadhacker

README.md

@@ -20,15 +20,29 @@ It does not work with simple compressed streams of data.
 You can create a new ZIP archive like this:
 
 ```csharp
-var zipArchive =
+var file =
     new ZipExtracted(
         new Zipped(
             "small.dat", new InputOf("I feel so compressed")
         ),
         "small.dat"
     ).Stream();
 ```
-
+or with multiple files
+```csharp
+new Zipped(
+    new Dictionary<string, IInput>()
+    {
+        {"small.dat", new InputOf("I feel so compressed") },
+        {"smaller.dat", new InputOf("I'm so compressed") }
+    }
+);
+
+new Zipped(
+    new KeyValuePair<string, IInput>("small.dat", new InputOf("I feel so compressed")),
+    new KeyValuePair<string, IInput>("smaller.dat", new InputOf("I'm so compressed"))
+);
+```
 Update a file in the ZIP:
 
 ```csharp
@@ -38,6 +52,15 @@ var updated =
         "Brave Citizens.txt", new InputOf("Edward Snowden")
     ).Stream();
 
+```
+or add a file to the ZIP if it doesn't exist
+```csharp
+var updated =
+    new ZipUpdated(
+        new Zipped("Brave Citizens.txt", new InputOf("Edward Snowden")),
+        "Concerned Citizens.txt", new InputOf("Donald")
+    ).Stream();
+
 ```
 
 Extract a file in the zip:
@@ -51,7 +74,7 @@ var extracted =
     ).Stream();
 ```
 
-List the contents of an archive:
+List the contents (directories and files) of an archive:
 
 ```csharp
 IEnumerable<string> contents =
@@ -60,6 +83,15 @@ IEnumerable<string> contents =
     );
 ```
 
+List all files only of an archive:
+
+```csharp
+IEnumerable<string> files =
+    new ZipFiles(
+        new InputOf(File.OpenRead("c:/some-zip-archive.zip")),
+    );
+```
+
 Remove a file from the archive:
 
 ```csharp
@@ -89,6 +121,16 @@ var isZip =
     ).Value();
 ```
 
+Test if a file exists in a zip:
+
+```csharp
+var exists =
+    new ZipContains(
+        new InputOf(File.OpenRead("c:/some-zip-archive.zip")),
+        "someFileInTheZip.txt")
+    ).Value();
+```
+
 Test if a file in a zip is protected with a password:
 
 ```csharp