Update dependencies#6

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thegengen wants to merge 4 commits intomasterfrom

Commits on Jan 18, 2018

Update dependencies
Eugen Minciu
committed
Fix activesupport dependency for older Rubies
Eugen Minciu
committed
Fix rdoc spec so it works with older rubies.
Eugen Minciu
committed
Fix rake dependency for older Rubies
Eugen Minciu
committed