Merge branch 'association-key' of https://github.com/durango/sequelize into durango-association-key
check mysql 5.6 as well
Revert "check mysql 5.6 as well"

This reverts commit 77e86a11747af91a8f822499ffe8ae67d16c2cf7.
just a small note
enforce omitNull to be false
Fixed up one off connection clients for Sequelize (if client is already defined simply callback rather than connecting again).