Fix android emulator when more than one device is used

Remove adb wait-for-device call as it raises error when there's more than one device and/or emulator currently running. Use adb -s <emulatorId> instead of adb -e, so having more than one device currently running will not raise errors. Add printing of "Waiting for initialization......" when logging level is info and adding "." for each retry cycle. Add --retryCount option, so you can define the exact number of retries that will be executed before the emulate operation fails.

Fixes: 
http://teampulse.telerik.com/view#item/277469
https://github.com/NativeScript/nativescript-cli/issues/116
Looks like a constant to me. You can make it a private static member and move it to the top of the class so that helps documenting the code.