Refactor events into their own package

Most of the existing actions are game actions (they control the player character)
so they live in actions.game. Eventually, there will be modules for different
kinds of actions that only apply to, e.g. modal UI.

erynrl/actions/result.py

@@ -0,0 +1,47 @@
+# Eryn Wells <eryn@erynwells.me>
+
+from typing import TYPE_CHECKING, Optional
+
+if TYPE_CHECKING:
+    from .action import Action
+
+class ActionResult:
+    '''The result of an Action.
+
+    `Action.perform()` returns an instance of this class to inform the caller of the result
+
+    Attributes
+    ----------
+    action : Action
+        The Action that was performed
+    success : bool, optional
+        True if the action succeeded
+    done : bool, optional
+        True if the action is complete, and no follow-up action is needed
+    alternate : Action, optional
+        An alternate action to perform if this action failed
+    '''
+
+    def __init__(self, action: 'Action', *,
+                 success: Optional[bool] = None,
+                 done: Optional[bool] = None,
+                 alternate: Optional['Action'] = None):
+        self.action = action
+        self.alternate = alternate
+
+        if success is not None:
+            self.success = success
+        elif alternate:
+            self.success = False
+        else:
+            self.success = True
+
+        if done is not None:
+            self.done = done
+        elif self.success:
+            self.done = True
+        else:
+            self.done = not alternate
+
+    def __repr__(self):
+        return f'{self.__class__.__name__}({self.action!r}, success={self.success}, done={self.done}, alternate={self.alternate!r})'