android/example: adjust sdk versions

Set minimal API to 2 and the target API to 23. It covers virtually all
devices present on the market.

examples/android/AndroidManifest.xml

@@ -3,7 +3,8 @@
       package="org.lisp.ecl"
       android:versionCode="1"
       android:versionName="1.0">
-    <uses-sdk android:minSdkVersion="19" />
+    <uses-sdk android:minSdkVersion="2" />
+    <uses-sdk android:targetSdkVersion="23" />
     <uses-permission android:name="android.permission.INTERNET" />
     <application android:label="@string/app_name"
                  android:debuggable="true">

examples/android/project.properties

@@ -11,4 +11,4 @@
 #proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
 
 # Project target.
-target=android-10
+target=android-23