Add verbosity level

Author: tomap

src/GitVersionCore/GitVersionCore.csproj

@@ -135,6 +135,7 @@
     <Compile Include="OutputVariables\VersionVariables.cs" />
     <Compile Include="SemanticVersionExtensions.cs" />
     <Compile Include="SemanticVersionFormatValues.cs" />
+    <Compile Include="VerbosityLevel.cs" />
     <Compile Include="VersionFilters\MinDateVersionFilter.cs" />
     <Compile Include="VersionFilters\IVersionFilter.cs" />
     <Compile Include="VersionFilters\ShaVersionFilter.cs" />

src/GitVersionCore/VerbosityLevel.cs

@@ -0,0 +1,10 @@
+namespace GitVersion
+{
+    public enum VerbosityLevel
+    {
+        None,
+        Error,
+        Warn,
+        Info
+    }
+}