[reSIProcate] Coverity scan enrolment, clang-analyzer

[Daniel Pocock <daniel@xxxxxxxxxxxxx>]

Coverity has a free web-based service for open source projects

I've enrolled reSIProcate and integrated it with the Travis-CI build.
They should give us a scan on every commit

If anybody has any difficulty accessing the scan results or difficulty
with the Travis builds, please contact me.

We may also try the clang-analyzer.  The only reason Travis is not
already doing clang builds in parallel with gcc is the missing asio
package in their servers.

I've also made further changes to the git mirroring so it should be much
more regular now.  Previously the sync would break and CI builds were
not happening, but now the build always happens within 90 minutes of a
commit.

Regards,

Daniel