Emit .input instead of .txt files in workspace (#625)

Related: #612 

* Update workspace.py

Changed extension to .input

* Update test_workspace.py

* changed key value pair in test_workspace bc of change of extension to .input in workspace.py, fixed issue #618

* removed unwanted directories

* Update seth.py

* Update seth.py

Change in Documentation issue #612

manticore/core/workspace.py

@@ -528,7 +528,7 @@ class ManticoreOutput(object):
             f.write(str(state.constraints))
 
     def save_input_symbols(self, state):
-        with self._named_stream('txt') as f:
+        with self._named_stream('input') as f:
             for symbol in state.input_symbols:
                 buf = solver.get_value(state.constraints, symbol)
                 f.write('%s: %s\n' % (symbol.name, repr(buf)))

manticore/seth.py

@@ -330,7 +330,7 @@ class ManticoreEVM(Manticore):
             :type balance: int or SValue
             :param address: the address for the new contract (optional)
             :type address: int or EVMAccount
-            :return: an EVMAccount
+            :return: an EVMAccount address (long)
         '''
         with self.locked_context('seth') as context:
             assert context['_pending_transaction'] is None
@@ -350,7 +350,7 @@ class ManticoreEVM(Manticore):
             :type balance: int or SValue
             :param address: the address for the new contract (optional)
             :type address: int or EVMAccount
-            :return: an EVMAccount
+            :return: an EVMAccount address (long)
         '''
         with self.locked_context('seth') as context:
            assert context['_pending_transaction'] is None

tests/test_workspace.py

@@ -106,5 +106,5 @@ class StateTest(unittest.TestCase):
         self.assertIn('smt', keys)
         self.assertIn('trace', keys)
         self.assertIn('messages', keys)
-        self.assertIn('txt', keys)
+        self.assertIn('input', keys)
         self.assertIn('pkl', keys)