dscanner - Drozer based post-build dynamic vulnerability scanner command

* New command `dscanner`, enables one to scan signed APKs with Drozer
 * Drozer is a dynamic vulnerability scanner for Android
 * Drozer runs in a emulator or on-device, this new `dscanner` command...
  * starts a docker image with Drozer and the Android Emulator pre-installed,
  * loads the signed APK into the emulator
  * activates Drozer automated tests for the APK
  * gathers the report output and places it next to the original APK
 * The Drozer docker image can be:
  * cached locally for re-use (just don't run --clean*)
  * retrieved from dockerhub.com for more efficient runtime
  * or be built from scratch (in the new "./docker" directory)
 * New "Vulnerability Scanning" documentation section (run gendocs.sh)

docker/enable_service.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python2
+
+from com.dtmilano.android.viewclient import ViewClient
+
+vc = ViewClient(*ViewClient.connectToDeviceOrExit())
+
+button = vc.findViewWithText("OFF")
+
+if button:
+    (x, y) = button.getXY()
+    button.touch()
+else:
+    print("Button not found. Is the app currently running?")
+    exit()
+
+print("Done!")