adjust to scipy changes, window functions have moved

also, slepian had been deprecated in scipy 1.1.0 and was removed in
1.6.0 so we need to do something about it in next obspy major release

setup.py

@@ -514,23 +514,26 @@
         ],
     'obspy.plugin.taper': [
         'cosine = obspy.signal.invsim:cosine_taper',
-        'barthann = scipy.signal:barthann',
-        'bartlett = scipy.signal:bartlett',
-        'blackman = scipy.signal:blackman',
-        'blackmanharris = scipy.signal:blackmanharris',
-        'bohman = scipy.signal:bohman',
-        'boxcar = scipy.signal:boxcar',
-        'chebwin = scipy.signal:chebwin',
-        'flattop = scipy.signal:flattop',
-        'gaussian = scipy.signal:gaussian',
-        'general_gaussian = scipy.signal:general_gaussian',
-        'hamming = scipy.signal:hamming',
-        'hann = scipy.signal:hann',
-        'kaiser = scipy.signal:kaiser',
-        'nuttall = scipy.signal:nuttall',
-        'parzen = scipy.signal:parzen',
-        'slepian = scipy.signal:slepian',
-        'triang = scipy.signal:triang',
+        'barthann = scipy.signal.windows:barthann',
+        'bartlett = scipy.signal.windows:bartlett',
+        'blackman = scipy.signal.windows:blackman',
+        'blackmanharris = scipy.signal.windows:blackmanharris',
+        'bohman = scipy.signal.windows:bohman',
+        'boxcar = scipy.signal.windows:boxcar',
+        'chebwin = scipy.signal.windows:chebwin',
+        'flattop = scipy.signal.windows:flattop',
+        'gaussian = scipy.signal.windows:gaussian',
+        'general_gaussian = scipy.signal.windows:general_gaussian',
+        'hamming = scipy.signal.windows:hamming',
+        'hann = scipy.signal.windows:hann',
+        'kaiser = scipy.signal.windows:kaiser',
+        'nuttall = scipy.signal.windows:nuttall',
+        'parzen = scipy.signal.windows:parzen',
+        # TODO slepian has been removed from scipy with version 1.6.0
+        # see https://docs.scipy.org/doc/scipy/release/1.1.0-notes.html
+        # see https://docs.scipy.org/doc/scipy/release/1.6.0-notes.html
+        'slepian = scipy.signal.windows:slepian',
+        'triang = scipy.signal.windows:triang',
         ],
     'obspy.plugin.trigger': [
         'recstalta = obspy.signal.trigger:recursive_sta_lta',