[WIP] copy apk and app files to dist directory

Add task `package` and `package-files` tasks that copy apt and app file to directory.

```
$ grunt cordova:build
...
$ grunt cordova:package-files
Copy to dist/android/CordovaApp-debug-unaligned.apk.
Copy to dist/android/CordovaApp-debug.apk.
Copy to dist/ios/emulator/HelloCordova.app.

Done, without errors.


Execution Time (2014-12-31 08:04:18 UTC)
loading tasks           1.2s  ▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 84%
cordova:package-files  224ms  ▇▇▇▇▇▇▇ 16%
Total 1.4s
```