Added requirements to requirements.txt and using cmd2

cmd_loop_main.py

@@ -0,0 +1,13 @@
+import cmd2
+
+
+class MainLoop(cmd2.Cmd):
+    """Loop for wordscape commands
+
+    """
+
+    def __init__(self):
+        letters = None
+        removed = set()
+
+        super().__init__()

requirements.txt

@@ -1 +1,3 @@
 pyspellchecker
+cmd2
+npyscreen