Merge pull request #32 from marcosrdz/patch-3

Update build.gradle

Author: gabidi

android/build.gradle

@@ -29,7 +29,7 @@ android {
   compileSdkVersion getExtOrIntegerDefault('compileSdkVersion')
   buildToolsVersion getExtOrDefault('buildToolsVersion')
   defaultConfig {
-    minSdkVersion 16
+    minSdkVersion rootProject.ext.has('minSdkVersion') ? rootProject.ext.minSdkVersion : 16
     targetSdkVersion getExtOrIntegerDefault('targetSdkVersion')
     versionCode 1
     versionName "1.0"