Always center protein in the viewport (e.g. during scrolling)

[#50752991]
Fix a few minor bugs related to genetic engine
Remove "Being a Ribosome" interactive

It was broken and had nothing differencing it from other DNA
interactives. Conversion of Classic DNA models with DNA in general
doesn't make sense, as we don't use anything from converted model.
Update "Mutations" interactive
Make DNA interactives public
Makefile: always regenerate interactives.json
cap <target> deploy:update cleans public folder first
tweaked guard file to allow for interactives in new sub-directories
light matter legacy mw and draft interactives
Fix jumping to next DNA state during states transition

[#51190373]
Cancel MD2D transitions when DNA state changes

[#51190373]
travis-ci: subsequent passing builds: don't notify irc
travis-ci: valid yaml structure for config

Using gem travis-lint is helpful:
http://about.travis-ci.org/docs/user/travis-lint/