Add .editorconfig
Add .editorconfig

This is for vim and other non-eclipse users.

hifive/hifive-pitalium-explorer,hifive/hifive-pitalium-explorer,hifive-snu/hifive-test-explorer,hifive-snu/hifive-test-explorer,hifive/hifive-test-explorer,hifive/hifive-pitalium-explorer,hifive/hifive-test-explorer,hifive/hifive-test-explorer,hifive-snu/hifive-test-explorer,hifive-snu/hifive-test-explorer,hifive/hifive-pitalium-explorer,hifive/hifive-test-explorer