Fix build for android below 21

In res directory there's values directory that is required for all android versions and directory called values-v21, which is required only for Android version 21. In case you do not have installed latest Android version, this directory should not be added to your project.
Add copyResValues method, which copies res/values directory and res/values-v<version_number> directory to your project. This way when we add directories for other android versions, they will not break builds for older ones.

Fixes #299

Author: rosen-vladimirov

lib/services/android-project-service.ts

@@ -14,6 +14,10 @@ import os = require("os");
 class AndroidProjectService implements IPlatformProjectService {
 	private SUPPORTED_TARGETS = ["android-17", "android-18", "android-19", "android-21"];
 	private static METADATA_DIRNAME = "__metadata";
+	private static RES_DIRNAME = "res";
+	private static VALUES_DIRNAME = "values";
+	private static VALUES_VERSION_DIRNAME_PREFIX = AndroidProjectService.VALUES_DIRNAME + "-v";
+
 	private targetApi: string;
 
 	constructor(private $androidEmulatorServices: Mobile.IEmulatorPlatformServices,
@@ -53,19 +57,20 @@ class AndroidProjectService implements IPlatformProjectService {
 	public createProject(projectRoot: string, frameworkDir: string): IFuture<void> {
 		return (() => {
 			this.$fs.ensureDirectoryExists(projectRoot).wait();
-
+			var newTarget = this.getLatestValidAndroidTarget(frameworkDir).wait();
+			var versionNumber = _.last(newTarget.split("-"));
 			if(options.symlink) {
-				this.copy(projectRoot, frameworkDir, "res", "-R").wait();
+				this.copyResValues(projectRoot, frameworkDir, versionNumber).wait();
 				this.copy(projectRoot, frameworkDir, ".project AndroidManifest.xml project.properties", "-f").wait();
 
 				this.symlinkDirectory("assets", projectRoot, frameworkDir).wait();
 				this.symlinkDirectory("libs", projectRoot, frameworkDir).wait();
 			} else {
-				this.copy(projectRoot, frameworkDir, "assets libs res", "-R").wait();
+				this.copyResValues(projectRoot, frameworkDir, versionNumber).wait();
+				this.copy(projectRoot, frameworkDir, "assets libs", "-R").wait();
 				this.copy(projectRoot, frameworkDir, ".project AndroidManifest.xml project.properties", "-f").wait();
 			}
 
-			var newTarget = this.getLatestValidAndroidTarget(frameworkDir).wait();
 			if(newTarget) {
 				this.updateTarget(projectRoot, newTarget).wait();
 			}
@@ -79,6 +84,21 @@ class AndroidProjectService implements IPlatformProjectService {
 		}).future<any>()();
 	}
 
+	private copyResValues(projectRoot: string, frameworkDir: string, versionNumber: string): IFuture<void> {
+		return (() => {
+			var resSourceDir = path.join(frameworkDir, AndroidProjectService.RES_DIRNAME);
+			var resDestinationDir = path.join(projectRoot, AndroidProjectService.RES_DIRNAME);
+			this.$fs.createDirectory(resDestinationDir).wait();
+			var versionDirName = AndroidProjectService.VALUES_VERSION_DIRNAME_PREFIX + versionNumber;
+			var directoriesToCopy = [AndroidProjectService.VALUES_DIRNAME];
+			if(this.$fs.exists(path.join(resSourceDir, versionDirName)).wait()) {
+				directoriesToCopy.push(versionDirName);
+			}
+
+			this.copy(resDestinationDir, resSourceDir, directoriesToCopy.join(" "), "-R").wait();
+		}).future<void>()();
+	}
+
 	public interpolateData(projectRoot: string): IFuture<void> {
 		return (() => {
 			// Interpolate the activity name and package