Add mixpanel to track user clicks

So we can better understand them, instead of making
wrong (or not) assumptions about what is the best for them.
added notification to survey project owners
fix draft and update email from field #changelog [Fix #43970369]
fixing subject and header of survey email
Merge branch 'master' of github.com:catarse/catarse
fix newsletter checkbox #changelog [Fix #46027807]
updated moip and httparty gems [fixes #46028641]
Merge branch 'master' of github.com:catarse/catarse
updated catarse_moip gem
fixed bizarre bugs with Psych (use syck)
Fix wrong monitoring click event @ mixpanel 

Sorry, I was looking for h4 a, but you can't hit it at all.