added Jan to developers
add frog image file
use hippo avatar instead of frog
Merge pull request #72 from cm-jan/added-jan

added Jan to developers
Merge branch 'added-jan' of github.com:christopheschwyzer/cargomedia.github.io into issue-74
Merge pull request #74 from christopheschwyzer/issue-74

Add Jan to dev
Merge branch 'master' of github.com:cargomedia/cargomedia.github.io into add-daniel

Conflicts:
	_data/members.yml