EOO: Apply pilot gain/tanh after IDFT.

[tmiw]

Updates EOO TX to apply pilot gain/tanh after executing IDFT. Previously this was done before IDFT, which didn't match up with the reference Python implementation.

Relevant Python code below:

    def set_eoo_bits(self, eoo_bits):
        Ns = self.Ns; Ncp = self.Ncp; M = self.M; Nc = self.Nc; Nmf = int((Ns+1)*(M+Ncp))

        eoo_syms = eoo_bits[::2] + 1j*eoo_bits[1::2]
        eoo_syms = torch.reshape(eoo_syms,(1,Ns-1,Nc))
        
        eoo_tx = torch.matmul(eoo_syms,self.Winv)
        if self.Ncp:
            eoo_tx_cp = torch.zeros((1,Ns-1,self.M+Ncp),dtype=torch.complex64)
            eoo_tx_cp[:,:,Ncp:] = eoo_tx
            eoo_tx_cp[:,:,:Ncp] = eoo_tx_cp[:,:,-Ncp:]
            eoo_tx = torch.reshape(eoo_tx_cp,(1,(Ns-1)*(self.M+Ncp)))*self.pilot_gain
            if self.bottleneck == 3:
                eoo_tx = torch.tanh(torch.abs(eoo_tx)) * torch.exp(1j*torch.angle(eoo_tx))
            self.eoo[0,2*(M+Ncp):Nmf] = eoo_tx

@drowe67 @peterbmarks

[tmiw]

I'm going to quickly build ms-rade-nopy from freedv-gui with this PR and see if the reporting tests all pass there.

[drowe67]

@peterbmarks both @tmiw & I are OK to merge this. If you are busy just let us know and either one of us can hit the green button.