fix thomas to follow the new view type abstraction, update test

Author: hdt5kt

pyzag/chunktime.py

@@ -336,6 +336,9 @@ def __init__(self, A, B, *args, **kwargs):
             raise TypeError("B must implement BlockViewOps.")
 
     def matvec(self, v):
+        """
+        call thomas_solve
+        """
         return thomas_solve(self.A, self.B, v)