added the possibility to cache locally downloaded tarballs (and git repos)

If the cache variable EP_CACHE_DIR is set, tarballs are taken from there if available, otherwise downloaded and copied there to avoid the download after a make clean.

mentioned in commit 49eea429

Status changed to merged

mentioned in merge request !26 (merged)

mentioned in commit bd1cfbd5

mentioned in commit 16fba33a

Mentioned in commit jwsmith/lcgcmake@49eea429

Mentioned in commit jwsmith/lcgcmake@bd1cfbd5