init - display test

new idf project (with  idf.py create-project)
add 2 components for encoder and display:
    https://github.com/DavidAntliff/esp32-rotary-encoder
    https://github.com/UncleRus/esp-idf-lib/tree/master/components/max7219
add code for testing a 7 segment display

.gitignore

@@ -0,0 +1,6 @@
+# ESP-IDF default build directory
+build
+
+# VIM files
+*.swp
+*.swo