Add gitignore file
-rw-r--r-- 416 .gitignore
drwxr-xr-x - adc
drwxr-xr-x - clkout
drwxr-xr-x - gpio_intr
drwxr-xr-x - i2c_bme280
drwxr-xr-x - i2c_light
drwxr-xr-x - i2c_temp
drwxr-xr-x - i2c_uv
drwxr-xr-x - i2c_vcnl4040
drwxr-xr-x - ledstrip
drwxr-xr-x - pwm
drwxr-xr-x - rom_uart