[pdal] First stab at Coverity Scan

[Howard Butler]

> On Dec 3, 2016, at 2:16 PM, Mateusz Loskot <mateusz at loskot.net> wrote:
> 
> I might give the latter a go if I have a moment.

Thanks for working through this. Coverity scans will be nice to have once we get over the docker hump.

Howard