Adding QWT package. (#4911)
Adding QWT package. (#4911)

* Adding QWT package.

* Using builtin file filtering.

* Formatting.

TheTimmy/spack,iulian787/spack,lgarren/spack,krafczyk/spack,iulian787/spack,skosukhin/spack,EmreAtes/spack,mfherbst/spack,skosukhin/spack,TheTimmy/spack,iulian787/spack,LLNL/spack,krafczyk/spack,EmreAtes/spack,skosukhin/spack,TheTimmy/spack,krafczyk/spack,mfherbst/spack,LLNL/spack,iulian787/spack,skosukhin/spack,matthiasdiener/spack,matthiasdiener/spack,lgarren/spack,tmerrick1/spack,EmreAtes/spack,EmreAtes/spack,tmerrick1/spack,skosukhin/spack,LLNL/spack,TheTimmy/spack,TheTimmy/spack,mfherbst/spack,lgarren/spack,mfherbst/spack,EmreAtes/spack,LLNL/spack,tmerrick1/spack,krafczyk/spack,tmerrick1/spack,iulian787/spack,LLNL/spack,tmerrick1/spack,lgarren/spack,mfherbst/spack,matthiasdiener/spack,matthiasdiener/spack,lgarren/spack,krafczyk/spack,matthiasdiener/spack