Upgraded apktool to version 2.0.0-RC2.

Merge https://github.com/appium/appium-adb/issues/64 after merging this.

In our app we have upgraded to apktool version 2.0.0-RC2 since it is required to process APKs generated by the Lollipop SDK. Currently, I'm patching my Appium installation with the new ``appium_apk_tools.jar``, but it would be nice to upgrade it in Appium if it is safe.

Without this fix, Appium fails to extract the app strings. Here's the relevant part of appium.log:
```
2014-11-14 09:55:22:098 - warn: Error getting strings.xml from apk
2014-11-14 09:55:22:099 - info: [debug] Exception in thread "main" brut.androlib.AndrolibException: Could not decode arsc file
	at brut.androlib.res.decoder.ARSCDecoder.decode(ARSCDecoder.java:54)
	at brut.androlib.res.AndrolibResources.getResPackagesFromApk(AndrolibResources.java:540)
	at brut.androlib.res.AndrolibResources.loadMainPkg(AndrolibResources.java:76)
	at brut.androlib.res.AndrolibResources.getResTable(AndrolibResources.java:68)
	at io.appium.apktools.StringsXML.run(StringsXML.java:84)
	at io.appium.apktools.Main.main(Main.java:31)
Caused by: java.io.IOException: Expected: 0x001c0001, got: 0x00000000
	at brut.util.ExtDataInput.skipCheckInt(ExtDataInput.java:48)
	at brut.androlib.res.decoder.StringBlock.read(StringBlock.java:43)
	at brut.androlib.res.decoder.ARSCDecoder.readPackage(ARSCDecoder.java:100)
	at brut.androlib.res.decoder.ARSCDecoder.readTable(ARSCDecoder.java:81)
	at brut.androlib.res.decoder.ARSCDecoder.decode(ARSCDecoder.java:49)
	... 5 more
```