dev-python/pywcsgrid2: Add ebuild for git version of pywcsgrid2

Package-Manager: portage-2.2.8-r1
dev-python/pywcsgrid2: Mask pywcsgrid2-9999 and remove keywords

Package-Manager: portage-2.2.8-r1
Merge pull request #186 from sargas/pywcsgrid2

dev-python/pywcsgrid2: Add ebuild for git version of pywcsgrid2