Should be up on github for you to try today or tomorrow. I hope you like it!
First drop of the (alpha) Arduino core for CMWX1ZZABZ-based boards here.
Here is a more or less complete how-to to get going with this STM32L0 Arduino core using the Arduino IDE with the Grasshopper development board. Just follow the instructions. Any question or trouble, send me an e-mail at tleracorp@gmail.com.