Intelligently determine location of title for Axes objects.

[v0dro]

Currently we simply get the center of the Axes and set the start point of the Axes title text from there.

However, this is not a good and scalable approach because it turns out rather ugly especially when the font size is larger. This issue will involve fixing the current situation by coming up with a better heuristic to determine the location of the title text for an Axes object.

Here's the current situation: