An initial implementation of debugger-compatible direct forwarding.
Fix iOS build.
Merge branch 'master' into landonf-mach-debugger-forwarding
Merge branch 'master' into landonf-mach-debugger-forwarding
Allow runtime selection between exception forwarding mechanisms.
Begin stubbing out the new format.
Add register, thread, and binary image data types.
Merge branch 'master' into landonf-mach-debugger-forwarding
Fix inverted logic when forwarding exception message.
Fix out-of-date comment
Expose the forwarding type configuration as API
Note that handlers can not correctly be removed.
Remove resolved TODO
Add support for registering either a thread or task-specific handler.
Begin stubbing out guarded/locking async-safe allocator.
Fix relative references to project resources.
Set a retina Default.png to quiesce Xcode warnings when building DemoCrash-iOS-Device
Add support for passing the mach task to the stack walker cursor.

Note that this is an incomplete commit, as the cursor is not currently
cleaned up and will leak the task port. I'm committing this partial
code because it's reliably reproducing a kernel deadlock/panic on the
iPhone 4, iPhone 4S. I haven't yet tested the iPhone 5.
Fix reset of exception ports for which a server was not previously registered.

This fixes the case where we register for exception types (via
FATAL_EXCEPTION_MASK) that were not registered to an existing server.
The ports in question would be left registered to our exception server
after it was stopped, which would result in a hang in the case where an
exception occured.

The fix is to reset all ports; in the case where a server was previously
registered, we re-insert it. In the case where none was registered, we
set the exception handler server port to MACH_PORT_NULL.

It remains the case that deregistering a mach exception server should
not generally be done, for the reasons described in the
deregisterHandlerAndReturnError: method documentation.
Fix relative references to project resources.