Update to scala 2.11

[jpivarski]

Some type inference changed, but my corrections for Scala 2.11 also work in Scala 2.10, so they must be correct corrections.

Also note:

• Count had been reading fromJsonFragment as JsonFloat, rather than JsonNumber, which made it fail on integers.
• Branch list reversal simplified by a library call.
• UntypedLabel policy changed: it can no longer see internal fill type inconsistencies, but it can infer the fill type from the first argument.