def vlq_encode_mappings(ary)
      ary.map { |group|
        group.map { |segment|
          vlq_encode(segment)
        }.join(',')
      }.join(';')
    end
def vlq_encode_mappings(ary)
      ary.map { |group|
        group.map { |segment|
          vlq_encode(segment)
        }.join(',')
      }.join(';')
    end
Public: Encode a mapping array into a compact VLQ string.

 ary - Two dimensional Array of Integers.

 Returns a VLQ encoded String seperated by , and ;.