Add crash_info feature

[pitag-ha]

The behavior cmd structure now supports dumping the Merlin response in three different forms:

• Full behavior.
• Reduction of the behavior to category data in the form of the response's return class, i.e. Return, Error, Exception etc.
• Reduction of the behavior to category data in the form of "Has the server crashed since the last query"?

The first two are implemented already. What's missing is the implementation of the third. That also requires a small change to Merlin.