MB-12864: Add Breakpad crash reporting

Add Google's Breakpad project to memcached so fatal errors will
be easier to diagnose, with finer details of system status
nearer to the time of the fatal error than is currently accessible.

- Support for Linux platforms and Windows.

- Adam Taylor's <adam.taylor@couchbase.com> Windows code is
  included, with minor alterations.

- Feature flags ensure memcached can still build without breakpad.

Google Breakpad available at https://code.google.com/p/google-breakpad/

Change-Id: I00de005b96dbd8517192aa26b1cbd5b9e464e9bf
Reviewed-on: http://review.couchbase.org/43708
Reviewed-by: David Haikney <david.haikney@couchbase.com>
Tested-by: buildbot <build@couchbase.com>