README.md: acknowledge recent contributors
README.md: acknowledge recent contributors

bulwahn/meta-ros,bmwcarit/meta-ros,rapyuta/meta-ros,bulwahn/meta-ros,simium/meta-ros,simium/meta-ros,bulwahn/meta-ros,simium/meta-ros,bmwcarit/meta-ros,bmwcarit/meta-ros,rapyuta/meta-ros,rapyuta/meta-ros,bmwcarit/meta-ros