DFT should use aligned memory blocks for best results. Also allocate one
extra sample for DFT output, just in case DFT zop is as bad as zrop.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>
Borrowing some DFT code from deadbeef, this implements a simple spectrum
visualization into the main toolbar of the app.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>