[make sameRoots lazy
Helmut Grohne <grohne@cs.uni-bonn.de>**20150206132236
 Ignore-this: d7eef64b8929f82a820c7e38a7bc300e
 
 I see no reason for it to be strict and the test suite improves by another 0.6%.
] hunk ./src/Syntax/Class/Antiunifier.hs 71
-sameRoots (x1:x2:xs) = (&&) (sameSymAtRoot x1 x2) $! sameRoots (x2:xs)                
+sameRoots (x1:x2:xs) = sameSymAtRoot x1 x2 && sameRoots (x2:xs)