Move to AndroidStudio, and fix some compile error, optimize codes.

First of all, thank you very much for this library. 
Then, I made some changes to this project ,and want to merge into your repository. The changes are as follows:
1. Move to Android Studio.
2. Move resources from the IconButton module to the Demo module.
3.Use ` xmlns:app="http://schemas.android.com/apk/res-auto"` and the flow code instead of use with `SafeParcelHelper`
```
        TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.IconButton);
        int paddingId = typedArray.getDimensionPixelSize(R.styleable.IconButton_iconPadding, 0);
        setIconPadding(paddingId);
        typedArray.recycle();
```

4. Reformat code.

In addition, I plan to publish the library to `jcenter`(www.bintray.com).