Added checkbox for creation of the desktop shortcut and branding text

Hello, 

I have added to the Julia installer a checkbox for the creation of the desktop shortcut and added the branding text too. In the processes I had to change the includes. Now Ithe script is including MUI2.nsh instead of MUI.nsh.

The following screenshots show the changes:

![image](https://cloud.githubusercontent.com/assets/442931/3387628/058aed0c-fc80-11e3-8b44-1272a5357d6f.png)

![image](https://cloud.githubusercontent.com/assets/442931/3387654/3504e718-fc80-11e3-9e5e-71dd7382a2e3.png)

Please let me know, if the changes are OK.

I can continue to contribute to this installer, so also new suggestions would be appreciated.

Regards,

Gil