add packages.config of cake

.gitignore

@@ -8,3 +8,6 @@ build/*
 !build/build.cake
 !build/build.nuspec
 !build/build.ps1
+!build/tools/
+build/tools/*
+!build/tools/packages.config

build/tools/packages.config

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+    <package id="Cake" version="0.35.0" />
+</packages>