tightfig

subtitle fix for the tightfig function from Richard Crozier ('Remove excess margins from figures.)

Added some modifications to the code by https://en.mathworks.com/matlabcentral/fileexchange/34055-tightfig-hfig

which is an amazing function that I have been using for years. The function 'sgtitle' introduced in R2018b is not covered with this function. This contribution fixes this.