Isis2pds App and Gtests (#4198)

* Isis2pds App and gtests

* Added pds4 conversion test

* isis2pds data added

* isis2pds Makefiles removed

* Added second function with cube parameter and removed unnecessary error checking.

* Updated added function with copy/paste error.

* Added bypass solution to segfault issue.

* Updated isis2pds(ui) function with SetVirtualBands.

* Updated isis2pds(ui) function with SetVirtualBands.

* Updated isis2pds(ui) function.

* Resolved segfault issues.