Implement support for generating a report without a crash

There have been a number of requests from various vendors to support generating 
a crash report without actually traversing the signal handler, eg, in the case 
of a failure that did not necessarily trigger a crash.

This would also solve some of the issues around exception handling and the need 
to trigger a signal from the uncaught exception handler.

I believe this task can be broken down into the following steps:

* Implement support for specifying the target plcrash_async_file_t when 
generating a crash report
* Add new public API that generates a report and returns the data as an NSData 
instance. This will be achieved by writing the report out to a temporary file, 
and mapping that file, and deleting the backing file. Alternatively we could 
add support for providing different plcrash_async_file_t implementations, but 
that involves more complexity in the async-safe code path for limited benefit.
* Add internal API for fetching the current thread context and using this to 
generate the report.

Original issue reported on code.google.com by landon.j.fuller@gmail.com on 9 Jul 2012 at 7:31

KeshaviPhone / plcrashreporter

Implement support for generating a report without a crash #46