Store/Context-related issues

[endorpersand]

• Stats & attendance depend on the delegateAttributes context field, but on stats/attendance reset, these fields reset to empty objects. This is handled by hacky patches, but could be fixed more elegantly.
• $lib/stores needs to be written in a way that supports more expressiveness than it has right now
• Persisted stores don't have any JSON validation, meaning invalid JSON schema can result in the site crashing until localStorage is cleared
• More data can be ported to persisted stores, such as Current Motion SL