title: Nuget pack does not honor number of digits on assembly version
body: <p>I need <code>nuget pack</code> to generate a package version with only 3 digits (we want to do semantic versioning on it) but when I call it on a csproj which has an <code>AssemblyVersion</code> attribute set to "1.0.0", the resulting nupkg file ends with version "1.0.0.0" in it's metadata (and file name). Why doesn't the command line tool honor the amount of digits specified on the <code>AssemblyVersion</code> attribute?</p>
  
  <p>I started this with a call to <code>nuget spec</code> against the csproj file, which generates a stub nuspec file like this (it actually includes more tags with placeholder values, but I've deleted them since we don't need them):</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;package &gt;
    &lt;metadata&gt;
      &lt;id&gt;$id$&lt;/id&gt;
      &lt;version&gt;$version$&lt;/version&gt;
      &lt;title&gt;$title$&lt;/title&gt;
      &lt;authors&gt;$author$&lt;/authors&gt;
      &lt;owners&gt;$author$&lt;/owners&gt;
      &lt;requireLicenseAcceptance&gt;false&lt;/requireLicenseAcceptance&gt;
      &lt;description&gt;$description$&lt;/description&gt;
      &lt;releaseNotes&gt;Release notes.&lt;/releaseNotes&gt;
      &lt;copyright&gt;Copyright 2015&lt;/copyright&gt;
    &lt;/metadata&gt;
  &lt;/package&gt;
  </code></pre>
  
  <p>With this nuspec file checked in TFS in the same folder as the csproj file, we can now call pack like this:</p>
  
  <pre><code>nuget pack MyProject.csproj
  </code></pre>
  
  <p>The project's AssemblyInfo.cs file contains a line to set the version explicitly:</p>
  
  <pre><code>[assembly: AssemblyVersion("1.0.0")]
  </code></pre>
  
  <p>It is all working perfectly fine, except for the fact that the tool is using 4 digits when it retrieves the assembly version. Even Windows shows the version with only 3 digits when I right click the dll on the file explorer and go to details. Why is NuGet using 4 digits? Am I perhaps missing something obvious?</p>
  
  <p>Hardcoding the version in the nuspec is obviously not ideal, because then we would have to maintain the version number in two different places while they are intended to be always the same. I mean, this was supposed to be the idea behind the special placeholder value <code>$version$</code> there that NuGet itself knows how to extract from the project.</p>