Fix SMT parsing; release v2.1.0.

Author: liffiton

Diff for: CHANGES_since_1.0

@@ -1,3 +1,7 @@
+2.1.0 - 2020-05-24
+------------------
+ * Fix SMT parsing (the z3 API changed at some point)
+
 2.0.1 - 2017-10-12
 ------------------
  * Add --print-mcses option to print MCS constraints instead of MSS constraints

Diff for: SMTsolvers.py

@@ -24,10 +24,10 @@ def read_dimacs(filename):
 
 def read_smt2(filename):
     formula = parse_smt2_file(filename)
-    if is_and(formula):
-        return formula.children()
+    if len(formula) == 1 and is_and(formula[0]):
+        return formula[0].children()
     else:
-        return [formula]
+        return formula
 
 
 class Z3SubsetSolver(object):

Diff for: VERSION

@@ -1 +1 @@
-2.0.1
+2.1.0