array merge was duplicating existing output params

[jonmifsud]

This would cause a performance issue, as it would duplicate all the output parameters, so in my case checking what dsParamPARAMOUTPUT was returning the following:

array(
    'date',
    'article',
    'article'
)

Thus running the same snippet of code twice, additionally it was also duplicating the output parameters, as seen below.

[jonmifsud]

@nilshoerrmann when you have some time just pull this in, just making the array merge unique to avoid duplicates.

[nilshoerrmann]

Thanks, Jon!