added integration docs for SQuirreL SQL
Merge pull request #1326 from crate/m/squirrel_docs

added integration docs for SQuirreL SQL
alteration to multi node best practice
Merge pull request #1325 from crate/h/multinodesetup2

alterations to multi node setup best practice
Require DataType of grouping keys in GroupProjector

GroupingProjector now takes the key dataTypes as argument.
Currently the types are un-used. But they will be used in
the future for circuit-breaker and probably type based
optimizations.