Initial Commit
Setup everything for acceptance testing
The basic form of a query: `for_all` and `return_as`
Introduce: Projections
First filter command
Change of the API to let documents act more like hashes, part 1

Change the API of the `return_as` block
Change of the API to let documents act more like hashes, part 2

Change the API of the `filter` block
A little bit of structure for the specs
Set something to a fixed value (not sure what this is good for)
Very simple case of sorting implemented
Add option to use descending order
Allow to sort with multiple parameters
Query#sort -> Query#sort_by
Query#filter -> Query#filter_by
Tiny cleanup
Implemented `limit`
Simplify Literal creation
Allow the offset to take a limit
An interactive console to try things out