Bookshelf: Updates of bookshelf dependencies

[Playrom]

Updates of bookshelf dependencies

Introduction

david-dm.org shows that we are behind in the support for a lot of our dependencies.

Does anybody propone itself to check if using the latest versions of all our dependencies breaks the project?

[jadengore]

@Playrom We could use greenkeeper.io to check our dependencies for us.

[Playrom]

never heard of It, seems nice

but it's a premium service, I think we don't have a budget

[ricardograca]

@Playrom it's free for open-source projects.

[ricardograca]

Fixed with PR #1616. All production dependencies are up to date now. Only some dev dependencies can't be updated immediately until we add the engines key to package.json to support only Node version 4 and newer.