Merge pull request #57 from hubuk/issue30

Fixed path to Microsoft.CodeContractAnalysis.targets for MSBuild v12.0.

Author: SergeyTeplyakov

Microsoft.Research/ManagedContract.Setup/MSBuild/v12.0/Microsoft.CodeContracts.targets

@@ -635,7 +635,7 @@
       Include Code Analysis target if present
     ======================================================================-->
   <PropertyGroup>
-    <CodeContractAnalysisTargets>$(CodeContractsInstallDir)MsBuild\v4.0\Microsoft.CodeContractAnalysis.targets</CodeContractAnalysisTargets>
+    <CodeContractAnalysisTargets>$(CodeContractsInstallDir)MsBuild\v12.0\Microsoft.CodeContractAnalysis.targets</CodeContractAnalysisTargets>
   </PropertyGroup>
   <Import Project="$(CodeContractAnalysisTargets)" Condition="Exists('$(CodeContractAnalysisTargets)')"/>