incorrect plot margins in correlate_factors_with_covariates

[cleiti]

The correlate_factors_with_covariates function with plot="r" parameter has a title that does not fit into the plot boundaries. This is not something that a user can fix from the outside, because the function outputs a readymade corrplot object that is not adjustable after creation. This requires a very simple fix, an addition of mar = c(0,0,3,0) into the arguments of the corrplot function inside of correlate_factors_with_covariates.

Hope you'll find a second to fix this one!