update to support building with NS 5+

Author: PeterStaev

platforms/android/include.gradle

@@ -1,4 +1,4 @@
 dependencies {
-    def supportVer = project.hasProperty("supportVersion") ? supportVersion : "+";
+    def supportVer = project.hasProperty("supportVersion") ? supportVersion : "26.0.0-alpha1";
     compile "com.android.support:recyclerview-v7:$supportVer"
-}
+}