Hey @halloween you can download the .kar files from CloudBees.
You have to put the .kar files into the ./openhab/addons/ folder and openHAB will extract them to the following path with the jar files.
openhab2/userdata/kar/openhab-addons-2.1.0-SNAPSHOT/org/openhab/binding/
Hope this solves your problem 
edit# Please note that the “openhab-addons-2.1.0-SNAPSHOT” can have a different name if you download a different version.
edit2#
Manual style would be: Clone the GIT
"cd openhab2-addons/addons/binding"
create the jar
"jar cf org.openhab.binding.mihome.jar org.openhab.binding.mihome"
Please note you have to make the jar executable “sudo chmod +x org.openhab.binding.mihome.jar”
SORRY! Typo!
It must be jar cf org.openhab.binding.mihome.jar org.openhab.binding.mihome