CAVA-0.8.2

bugfixes:

• fix buffer overflow in audio buffer when calling reset_buffer (used in fifo input)
• cavacore: fix segfault when setting 0Hz lower cut off
• framerate <= 1 msec wait was multiplied by 1000 instead of divided

improvements:

• cavacore: don't print to stdout or call exit, use error status flag in cava_plan instead
• cavacore: add extern C construct for c++ compilers
• add license in cavacore header file
• remove build dependency on xxd, use incbin instead