Includes the novel keys of arb2Contents in the arb1Contents
and returns the result of the merge. In case of discrepances of
the values for the same key, the arb2Contents will prevail
Sorts the .arb formatted String arbContents in alphabetical order
of the keys, with the @key portion added below it's respective key
Optionally you can provide a compareFunction for customizing the sorting.
For simplicity sake there are common sorting features you can use when not
defining the former parameter