Use send only where necessary

Created by: cirosantilli

Prefer public_send if methods are public, and method calls if the method is a constant symbol.

public_send mentioned in bbatsov: https://github.com/bbatsov/ruby-style-guide#prefer-public-send

Under app and lib:

find . -iname "*.rb" | xargs perl -lapi -e 's/\.send\b/.public_send/'

but some manual refactor was also done in addition.

Exceptions:

• self.send and just send. I moved self.send to just send for uniformity and to avoid hound barks. In those cases, the call can access private methods, so it does not matter.
• at lib/redcarpet/render/gitlab_html there is an h.send which causes problems is replaced... seems like we are using something we shouldn't.