Attempt to support older API up to 15.

[yccheok]

Hi @divyanshub024

I just modified your drawing library, to support older API up to 15. Not sure you are interested to make it part of your official release?

Thank you very much.

[yccheok]

Hi @divyanshub024,

If you're interested to pick up this patch, please use app:tint instead of android:tint for ImageView XML tag.

Please kindly refer to

https://github.com/yccheok/AndroidDraw/commit/63f5283bb655a1dfdd29b172253dfc043104a0df

https://stackoverflow.com/questions/19500039/how-to-use-selector-to-tint-imageview-in-android

Thank you.