Add tuple comma when not in BUILD_LIST_n

Fixes issue #57

bin/uncompile.py: --verify now works on a single bytecode file. We will
set the output to be something created by tempfile.mktemps

test/simple_source/expression/03_tuple_assign.py

@@ -0,0 +1,7 @@
+# Github Issue #57 with Python 2.7
+def some_function():
+    return ['some_string']
+
+def some_other_function():
+    some_variable, = some_function()
+    print(some_variable)