use sdk 22 for gradle builds too; rename apk file based on git revision number

xwords4/android/XWords4/app/build.gradle

@@ -19,7 +19,7 @@ android {
     buildToolsVersion "22.0.1"
     defaultConfig {
         minSdkVersion 7
-        targetSdkVersion 14
+        targetSdkVersion 22
     }
 
     // Rename all output artifacts to include version information
@@ -103,6 +103,15 @@ android {
     lintOptions {
         abortOnError false
     }
+
+    def gitrev = "git describe --tags".execute().text
+    applicationVariants.all { variant ->
+        variant.outputs.each { output ->
+            output.outputFile = 
+            new File(output.outputFile.parent,
+                     output.outputFile.name.replace(".apk", "-${gitrev}.apk"))
+        }
+    }
 }
 
 dependencies {

xwords4/android/XWords4/build.gradle

@@ -26,7 +26,7 @@ subprojects {
     afterEvaluate {project ->
         if (project.hasProperty("android")) {
             android {
-                compileSdkVersion 14
+                compileSdkVersion 22
                 buildToolsVersion '22.0.1'
             }
         }