Run parser: deserialize the AutoSplitterSettings

[AlexKnauth]

Based on the work of @Refragg, I updated it to use the new settings map and settings value types.

• [x] Make sure the auto-splitter gets the settings from a freshly opened splits file.
• [x] Make sure a saved splits file gets the settings from the autosplitter, when the autosplitter has edited them.
• [x] Make sure a saved splits file gets to keep its Legacy XML, when the autosplitter has no settings of its own to replace it with.