Updated readme to include missing switches

Author: Jake Ginnivan

GitVersion/ArgumentParser.cs

@@ -63,7 +63,7 @@ public static Arguments ParseArguments(List<string> commandLineArguments)
                     arguments.LogFilePath = value;
                     continue;
                 }
-                
+
                 if (IsSwitch("url", name))
                 {
                     arguments.TargetUrl = value;

GitVersion/HelpWriter.cs

@@ -9,7 +9,7 @@ public static void Write()
             var message =
 @"Use convention to derive a SemVer product version from a GitFlow or GitHub based repository.
 
-GitVersion [path] [/l logFilePath] [/exec executable] [/execargs args]
+GitVersion [path] [/l logFilePath]
 
     path       The directory containing .git. If not defined current directory is used.
     /url       Url to remote git repository.