Also, reducing the VBR rate on panned mono

This reverts commit 9f407afa.

Also added 3rd clause to "master" COPYING file

Got authorization from all copyright holders

introduced in Thorvald's previous patch.

instead of relying on the one previously transmitted by the encoder.

find_spectral_pitch()

This involved adding kfft_single.[ch] that redefines kiss_fft a second time
with a different prefix. All this is still a bit of a mess now. The mask
had to be converted to 16-bit input, but we're still using floats to apply it.

copyright, so it's fine!)

pre-computed (instead of computing tons of pow() uselessly all the time)

Code much leaner now.