Add AndroidStudio gitignore file

AndroidStudio.gitignore

+# Built application files
+*.apk
+*.ap_
+
+# Files for the Dalvik VM
+*.dex
+
+# Java class files
+*.class
+
+# Generated files
+bin/
+gen/
+
+# Gradle files
+.gradle/
+build/
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Proguard folder generated by Eclipse
+proguard/
+
+# IDE specific configuration
+.idea
+
+# Intellij module files
+*.iml
+
+# Crashlytics auto-generated file for Android Studio plugin
+com_crashlytics_export_strings.xml