fix UDP test

After allowing IPv6 UDP test may fail because 'localhost' can be resolved as ::1
whereas UDP server listens on IPv4 interface. This enforces IPv4 also for client
Merge branch 'maint'
fft: fixed Nuttall window naming from nuttal to nuttall.

The old calls to nuttal are still there to preserve the API but they just point to the nuttall versions and their docs have been updated to indicate these calls are deprecated. Will be removed in 3.8.