Working from Icy-App GitHub
Using the Icy-App GitHub project as library source provides some advantages as staying up to date with current ICY version or access to future features and prepare your plugin for that.
Install Git plugin for Eclipse (if not already done).
Import Icy-App project.
Install Icy4Eclipse plugin (if not already done).
Configure Icy4Eclipse to work from Icy-App
You're now ready to work from Icy-App repository.
You can choose release (release version) or master (WIP development) branch depending what you want to do.