Add sorting to matrix editor + max rows i config

Sorting is added to the max editor and i config max row can be set.
Furthermore row can be added below selected row.
When sorting the row labels keep their positions from set in config
otherwise there need some updating, e.g. store labels in an array and
update the index. But I guess when using row label I assume they would
be "static" so they keep the order set from config.
Change key "addrows" to "mangerows"
Merge pull request #1 from bjarnef/master

Add sorting to matrix editor + max rows i config