Update _merge_allc.py

in Python 3, the next() method has been replaced by the __next__() method for iterators

Author: KailiBio

ALLCools/_merge_allc.py

@@ -40,7 +40,7 @@ def __init__(self, path, region):
             self.f_region = TabixIterator()
 
     def readline(self):
-        return self.f_region.next()
+        return next(self.f_region)
 
     def close(self):
         self.f.close()