add link to SDK references for android-support jar

I tried lots of things to make it more general, but the implementation of
this jar properties file is just too simple, so no variables can be used.

I renamed the other files related to android-support to match the naming
scheme.

libs/android-support-v4.jar.properties

@@ -0,0 +1,8 @@
+src=android-support-v4.jar
+doc=/opt/android-sdk/docs/reference
+# The String value of 'doc' is handed straight to `new java.io.File()` so it
+# is not possible to use variables.  Therefore, change "/opt/android-sdk" to
+# the path to your Android SDK, i.e. the value of $ANDROID_HOME or ${sdk.dir}
+#
+# Here's the relevant source:
+# https://android-review.googlesource.com/#/c/35702/3/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/project/LibraryClasspathContainerInitializer.java