Evaluate minEvents gating argument for CytoExploreR.

[djhammill]

@mikejiang, a recent change in the latest version of R is causing issues for CytoExploreR.

I've tracked down the issue as described in this ticket.

Basically all gating arguments are passed in as calls which get automatically evaluated during this do.call() chunk which invokes the gating function. The minEvents argument is dropped from this list and therefore remains a call when the event number check is performed.

To be safe I have wrapped the call evaluation in an if statement.

Adding @mikejiang for review as this fix is required on BioC for CytoExploreR to work - first reported here.

[mikejiang]

Thank you for the investigation&&patch

[mikejiang]

pushed to bioconductor