Add contrib and examples to sdist.
Add contrib and examples to sdist.

Just noticed I missed these last time.  Again, when building from source
these niceties come in handy if the user so desires them.

badcure/supernova,coreypobrien/supernova,badcure/supernova,major/supernova,lmaycotte/supernova,roaet/supernova,swyytch/supernova,coreypobrien/supernova,lmaycotte/supernova,immanetize/supernova,roaet/supernova,major/supernova,immanetize/supernova,swyytch/supernova