Entry completion popup supports rgba visual if available

We need this for the knowledge apps and encylopedia app. This comes
in upstream in the form of csd for popup windows but that's not
feasible to cherry pick. This should be an quick interim solution
that doesn't break anything
[endlessm/eos-sdk#688]
Merge pull request #5 from endlessm/sdk/688

Entry completion popup supports rgba visual if available