Added cake.build script

.gitignore

@@ -1,4 +1,6 @@
 bin/
 obj/
 packages/
+nupkg/
 *.userprefs
+.nugetapikey

Cake.Xamarin.nuspec

@@ -17,12 +17,12 @@
       <tags>Cake Script Build Xamarin</tags>
 
       <dependencies>
-         <dependency id="Cake.Core" />
+         <dependency id="Cake.Core" version="0.5.2" />
       </dependencies>
    </metadata>
 
    <files>
-      <file src="Cake.Xamarin\bin\Release\Cake.Xamarin.dll" target="lib/net45" />
-      <file src="Cake.Xamarin\bin\Release\Cake.Xamarin.xml" target="lib/net45" />      
+      <file src="./Cake.Xamarin/bin/Release/Cake.Xamarin.dll" target="lib/net45" />
+      <file src="./Cake.Xamarin/bin/Release/Cake.Xamarin.xml" target="lib/net45" />      
    </files>
 </package>

build.cake

@@ -0,0 +1,46 @@
+var sln = "./Cake.Xamarin.sln";
+var nuspec = "./Cake.Xamarin.nuspec";
+
+var target = Argument ("target", "lib");
+
+Task ("lib").Does (() => 
+{
+	NuGetRestore (sln);
+
+	DotNetBuild (sln, c => c.Configuration = "Release");
+});
+
+Task ("nuget").IsDependentOn ("lib").Does (() => 
+{
+	CreateDirectory ("./nupkg/");
+
+	NuGetPack (nuspec, new NuGetPackSettings { 
+		Verbosity = NuGetVerbosity.Detailed,
+		OutputDirectory = "./nupkg/",
+		// NuGet messes up path on mac, so let's add ./ in front again
+		BasePath = "././",
+	});	
+});
+
+Task ("push").IsDependentOn ("nuget").Does (() =>
+{
+	// Get the newest (by last write time) to publish
+	var newestNupkg = GetFiles ("nupkg/*.nupkg")
+		.OrderBy (f => new System.IO.FileInfo (f.FullPath).LastWriteTimeUtc)
+		.LastOrDefault ();
+
+	var apiKey = TransformTextFile ("./.nugetapikey").ToString ();
+
+	NuGetPush (newestNupkg, new NuGetPushSettings { 
+		Verbosity = NuGetVerbosity.Detailed,
+		ApiKey = apiKey
+	});
+});
+
+Task ("clean").Does (() => 
+{
+	CleanDirectories ("./**/bin");
+	CleanDirectories ("./**/obj");
+});
+
+RunTarget (target);