Refactor Fluent CloudFlow.collect to return generic #seq<_>
Refactor Fluent CloudFlow.collect to return generic #seq<_>

mbraceproject/MBrace.Core,krontogiannis/MBrace.Core,mbraceproject/MBrace.Core,dsyme/MBrace.Core,npmurphy/MBrace.Core,palladin/MBrace.Core,krontogiannis/MBrace.Core,palladin/MBrace.Core,npmurphy/MBrace.Core,dsyme/MBrace.Core