Port changes:
* Change to DISTVERSION
* Change to github
Bump x11/pantheon-terminal and math/pantheon-calculator
While in math/pantheon-calculator:
* Add LICENSE_FILE
While in x11/pantheon-terminal:
* Add missing dependencies in LIB_DEPENDS
* Add missing dependencies in USE_GNOME
* Group USExx accorfing to the portlint warning
* Change USES=cmake to USES=cmake:outsource
PR: 226696
Submitted by: Greg V <greg@unrelenting.technology>