Report crashes to improve Jaguar stability

[kasperl]

Anonymous crash reports can significantly improve the stability of Jaguar over time. When jag crashes, it would be good to gather non-personal information about the crash for analysis. Something along the lines of:

• The version of Jaguar.
• The name and version of your host operating system.
• The stack trace generated by the crash, which contains references to jag's own code and contains no references to your application code.