- use gbser_read_wait() to read multiple bytes where possible

- use gbser_read_wait() to read multiple bytes where possible
- remove disabled code along with the surrounding #if 0
- dynarray16_alloc(): use descriptive variable name "oldcount" instead of "i"
- dg100_recv_frame(): don't call dg100_debug() to print the buffer if it
  doesn't contain the expected number of chars