Fixing versions

- Added --version-suffix to build and publish
- Support reading DOTNET_* version variables everywhere versions can be read
- Show the commit sha in dotnet --version
- Added tests that check the assembly output version
- Set DOTNET_BUILD_VERSION when producing the CLI app itself so that it has the version information stamped in for help.

scripts/Microsoft.DotNet.Cli.Build.Framework/Command.cs

@@ -135,12 +135,18 @@ namespace Microsoft.DotNet.Cli.Build.Framework
 
         public Command Environment(IDictionary<string, string> env)
         {
-            foreach(var item in env)
+            foreach (var item in env)
             {
                 _process.StartInfo.Environment[item.Key] = item.Value;
             }
             return this;
         }
+        
+        public Command Environment(string key, string value)
+        {
+            _process.StartInfo.Environment[key] = value;
+            return this;
+        }
 
         public CommandResult Execute()
         {