Adding new capabilities to startApp in android adb, updating adb.startApp in appium, adding a test and updating package.json,caps.md and appium-adb submodule. 

-Related to #2026
-Added new capabilities intentAction, intentCategory, intentFlags, optionalIntentArguments and defaulting them. 
-Added new test to launch activity with a category
-Updated caps.md
-Made sure that adb.startApp is called with object which all properties corresponding to appium-adb 1.1.0
-updated package.json 
-updated submodule commit to point to new minor of appium-adb.
Ok :+1:  np ill change appium-adb interface yes having cb as second parameter makes more sense.