Remove nam::DSP::finalize_()

[sdatkinson]

Description

Breaking change. Following this, Code calling NAM should not do (e.g.):

model->process(input, output, numFrames);
model->finalize_(numFrames);

and instead just do

model->process(input, output, numFrames);

And subclasses shall take care of any preparation for the next call to process themselves.

Subclasses that don't override nor extend DSP::finalize_():

• Base
• Gain
• History
• LSTM

Subclasses where some change was needed:

• Buffer: This advanced the input buffer. Made an equivalent protected method _advance_input_buffer_() that subclasses can still use.
• WaveNet: Move _advance_buffers_() inside of process.

Subclasses of Buffer also needed to be checked:

• ConvNet: doesn't override, so _advance_input_buffer_() is pulled inside of process()
• Linear: Same

Testing

I checked a render before and after using a typical WaveNet and ensured that they're the same.

[sdatkinson]

Resolves #99