Add softprompt support (for real this time)

Is this too much voodoo for our purposes?

extensions/character_bias/script.py

@@ -0,0 +1,27 @@
+params = {
+    "bias string": " *I speak in an annoyingly cute way*",
+}
+
+def input_modifier(string):
+    """
+    This function is applied to your text inputs before
+    they are fed into the model.
+    """ 
+
+    return string
+
+def output_modifier(string):
+    """
+    This function is applied to the model outputs.
+    """
+
+    return string
+
+def bot_prefix_modifier(string):
+    """
+    This function is only applied in chat mode. It modifies
+    the prefix text for the Bot and can be used to bias its
+    behavior.
+    """
+
+    return string + params["bias string"]