add release notes from 2.1 series don't note again in 2.2.0 release notes things that were added in 2.1 series several small rewordings
add release notes from 2.1 series
don't note again in 2.2.0 release notes things that were added in 2.1 series
several small rewordings

cdsteinkuehler/MachineKit,ianmcmahon/linuxcnc-mirror,RunningLight/machinekit,yishinli/emc2,ianmcmahon/linuxcnc-mirror,bmwiedemann/linuxcnc-mirror,strahlex/machinekit,aschiffler/linuxcnc,ikcalB/linuxcnc-mirror,araisrobo/linuxcnc,araisrobo/machinekit,unseenlaser/machinekit,bobvanderlinden/machinekit,ArcEye/machinekit-testing,narogon/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,unseenlaser/linuxcnc,unseenlaser/machinekit,ArcEye/machinekit-testing,ArcEye/machinekit-testing,aschiffler/linuxcnc,strahlex/machinekit,Cid427/machinekit,EqAfrica/machinekit,cdsteinkuehler/linuxcnc,Cid427/machinekit,RunningLight/machinekit,bmwiedemann/linuxcnc-mirror,narogon/linuxcnc,ikcalB/linuxcnc-mirror,unseenlaser/linuxcnc,RunningLight/machinekit,ArcEye/MK-Qt5,cnc-club/linuxcnc,ianmcmahon/linuxcnc-mirror,RunningLight/machinekit,mhaberler/machinekit,Cid427/machinekit,yishinli/emc2,unseenlaser/linuxcnc,mhaberler/machinekit,araisrobo/linuxcnc,ianmcmahon/linuxcnc-mirror,araisrobo/machinekit,unseenlaser/machinekit,araisrobo/machinekit,jaguarcat79/ILC-with-LinuxCNC,RunningLight/machinekit,mhaberler/machinekit,kinsamanka/machinekit,unseenlaser/linuxcnc,EqAfrica/machinekit,RunningLight/machinekit,ArcEye/machinekit-testing,kinsamanka/machinekit,bobvanderlinden/machinekit,aschiffler/linuxcnc,jaguarcat79/ILC-with-LinuxCNC,araisrobo/linuxcnc,unseenlaser/machinekit,jaguarcat79/ILC-with-LinuxCNC,strahlex/machinekit,yishinli/emc2,mhaberler/machinekit,yishinli/emc2,kinsamanka/machinekit,narogon/linuxcnc,ianmcmahon/linuxcnc-mirror,ArcEye/MK-Qt5,araisrobo/machinekit,bobvanderlinden/machinekit,ArcEye/MK-Qt5,unseenlaser/machinekit,araisrobo/machinekit,kinsamanka/machinekit,kinsamanka/machinekit,mhaberler/machinekit,ianmcmahon/linuxcnc-mirror,cdsteinkuehler/linuxcnc,araisrobo/machinekit,aschiffler/linuxcnc,Cid427/machinekit,mhaberler/machinekit,Cid427/machinekit,Cid427/machinekit,narogon/linuxcnc,cdsteinkuehler/MachineKit,bobvanderlinden/machinekit,ianmcmahon/linuxcnc-mirror,aschiffler/linuxcnc,strahlex/machinekit,araisrobo/machinekit,ikcalB/linuxcnc-mirror,bobvanderlinden/machinekit,EqAfrica/machinekit,mhaberler/machinekit,jaguarcat79/ILC-with-LinuxCNC,bmwiedemann/linuxcnc-mirror,bmwiedemann/linuxcnc-mirror,kinsamanka/machinekit,cdsteinkuehler/linuxcnc,ArcEye/MK-Qt5,strahlex/machinekit,araisrobo/linuxcnc,RunningLight/machinekit,ArcEye/machinekit-testing,cdsteinkuehler/linuxcnc,EqAfrica/machinekit,unseenlaser/linuxcnc,araisrobo/machinekit,EqAfrica/machinekit,kinsamanka/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/MachineKit,narogon/linuxcnc,Cid427/machinekit,ikcalB/linuxcnc-mirror,cdsteinkuehler/MachineKit,strahlex/machinekit,ArcEye/MK-Qt5,EqAfrica/machinekit,cdsteinkuehler/linuxcnc,ArcEye/machinekit-testing,cnc-club/linuxcnc,Cid427/machinekit,cdsteinkuehler/MachineKit,unseenlaser/machinekit,unseenlaser/machinekit,ArcEye/MK-Qt5,bobvanderlinden/machinekit,strahlex/machinekit,unseenlaser/machinekit,bmwiedemann/linuxcnc-mirror,mhaberler/machinekit,ArcEye/MK-Qt5,araisrobo/machinekit,bmwiedemann/linuxcnc-mirror,ArcEye/machinekit-testing,ArcEye/MK-Qt5,kinsamanka/machinekit,bmwiedemann/linuxcnc-mirror,cdsteinkuehler/MachineKit,araisrobo/linuxcnc,cnc-club/linuxcnc,cnc-club/linuxcnc,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,bobvanderlinden/machinekit,cnc-club/linuxcnc,cnc-club/linuxcnc,cnc-club/linuxcnc,cdsteinkuehler/linuxcnc,ArcEye/machinekit-testing,ikcalB/linuxcnc-mirror,RunningLight/machinekit,EqAfrica/machinekit,EqAfrica/machinekit