Automatic update of char sheet

[lozanoje]

Calculate derived stats: stress Calculate bonus to attributes Calculate redution to stress due to fatigue Calculate injuries.count based on injury1.text, injury2.text and injury3.text, also for injuries.treated - might be useful for tracking-resources modules like Bar Brawl

[Muttley]

Splitting this into multiple tickets for clarity:

• [ ] #54
• [ ] #55
• [ ] #57