Revised methods for title slides

Found we only had methods for some sizes, and didn't have a consistent way to
fiddle the formatting when you wanted *almost* that slide with a little
difference.

Also has a hacky vertical alignment that works ok for single lines of text.
Worth improving later, but gets it done for now.
I can totally see how that is annoying :) Good point.

I'm unsure about having them at the top level, though, as they are polluting the global name space. In the light of this I feel that maybe just name spacing them under `Wingtips` might be a worthwhile compromise?

Not namespacing things feels like I'll get a concerned look from my old mentor :)