Merge fork with enhancements/fixes

[kalinon]

My fork has been getting a bit ahead so i wanted to open a PR with my working branch.

This includes the following bug fixes:

• fix allowing enum columns
• #455
• #454
• Fix issue where primary key can be pushed twice on create
• fix infinite recursion when searching with enum

It also includes the following enhancements:

• ameba recomendations
• add retry to adapter base
• add support for querying with Array(UUID)
• add Relationship annotation that is applied to methods which are defined relationships

[SebastianSzturo]

Any chance to get these fixes merged?

[confact]

ping @drujensen - Could this be merged? It solves some of my issues :)

[confact]

@kalinon could you split this one up into smaller MR (one for each fix preferably) - So it is easier to review and maybe approve it?

[robacarp]

related: #462

[kalinon]

@confact i had already done that, but they were never merged. It soon grew and was hard to manage for me. #454, #455 are smaller pieces of this.