Added list comprehension
Added SliceExpression
Added parsing for the new slice operator

o Numbers need at least one digit after a period to be parsed as numbers
o Introduced new parser level in Expressions to handle slices
Added single element collection access
Maps (including nodes and relationships) can be treated as collections

o Map type is a subtype of Collection(AnyType) instead of Scalar
o CollectionSupport treats maps as collections of collections
o UpdateAction.exec takes QueryState as an implicit val
o Introduced CompileTimeQueryState for actions that need a QueryState
   outside at execution plan building
Makes it possible to have Cypher queries with only RETURN
Index accessing can now be done from the end with negative numbers
Adds literal maps
Test fixes for literal maps
Added exception for list comprehension errors
Made output of maps more readable
Removed createProperty
Added documentation for collections and maps
Fixes documentation errors
Fixes documentation errors #2
Fixes documentation errors #3
Added better map access support
Fixes documentation errors #4