First fix for user reported issue

Fix for #1

• Update for situations where there are no subdirectories under /grnltr, just wav files with no grnltr.cfg
• Added elf files to the release package

The attached bin file can be flashed to the pod via DFU using:

dfu-util -a 0 -s 0x08000000:leave -D grnltr_pod.v0.99e.bin -d ,0483:df11

To program and elf file via openocd and a stlink:

 openocd -s /usr/local/share/openocd/scripts -f interface/stlink.cfg -f target/stm32h7x.cfg \
	-c "program ./build/grnltr_pod.v0.99.elf verify reset exit"

Replace grnltr_pod.v0.99e.bin with grnltr_bluemchen.v0.99e.bin above for the bluemchen.