[mythtv] LastFM support in MythMusic

[Anduin Withers]

> The test example in md5.c passes an uint64_t which would be 8 bytes
> would it not?
> 
> uint64_t md5val;
> av_md5_sum( (uint8_t*)&md5val, in,  1000); printf("%"PRId64"\n", md5val);

It would, the problem is in assuming the test is valid. The test stomps the
stack (print i before the first call to av_md5_sum, then after).

In av_md5_final() dst is treated as an array of four uint32_t (this also
matches the expected MD5 hex string of 32 characters).

--
Anduin Withers