add script to clean up gists

The script cleans up gists from closed/merged PR's.
replaced sse3 option in amd by mavx option
clean_gists.py: added options
clean_gists: implement all options

Everything should work now
clean_gists: delete closed pr gists by default
clean_gists: fix bug when description is empty
add Python version check in 'eb' command
Merge branch 'v1.15.x' into develop
fix version to v1.16.0dev
fix $MODULEPATH extensions for Clang/CUDA, include versionsuffix in module subdir
fix tiny remark
fix unit tests broken due to shellshock patch
fix broken test
fix case where testing is not enabled in modulestool.py tests
fix long line
fix broken test that verifies mismatch on 'module' function
fix remark
Merge pull request #1051 from boegel/fix_tests_broken_due_to_shellshock

fix unit tests broken due to shellshock patch
Merge branch 'develop' into fix_HMNS_goolfc_cgoolf
add definition of gimpi toolchain