Small fix for winwcp files.

The sampling rate can be slightly over segment due to float precision.
The previous implementation  raise error for some random files.

Author: samuelgarcia

neo/rawio/winwcprawio.py

@@ -72,9 +72,9 @@ def _parse_header(self):
 
                 all_sampling_interval.append(analysisHeader['SamplingInterval'])
 
-        assert np.unique(all_sampling_interval).size == 1
-
-        self._sampling_rate = 1. / all_sampling_interval[0]
+        # sampling interval can be slightly due to float precision
+        # all_sampling_interval are not always unique
+        self._sampling_rate = 1. / np.median(all_sampling_interval)
 
         signal_channels = []
         for c in range(header['NC']):