Fix return value of FreeTypeFont.textsize() does not include font offsets

[tk0miya]

Fixes #644

[coveralls]

Coverage increased (+0.0%) when pulling 60628c7 on tk0miya:master into 6c0fcef on python-pillow:master.

[wiredfool]

This is going to change the rendering for anyone who's got code that uses textsize. We should be very reluctant to break peoples code like that, especially since it's a silent break that changes the behavior.

[aclark4life]

True, I would deprecate in the next release & fix in the next next release. So this PR should add a deprecation warning… and nothing else. Maybe.

[wiredfool]

Perhaps getBoundingBox as a new api?

We should also be thinking about incorporating some of the metrics in a decent api, so that people can place the text accurately. That had come up in an issue or two before. (a: size is lost once youmake the font, and b: metrics are very ill defined from the various methods).

[tk0miya]

In PIL-1.1.7 and Pillow-2.1.0, ImageDraw#textsize() and ImageFont.textsize() return size of bounding box for text.
but after Pillow-2.2.0, these methods return size of text (without offset).

This change came from #185 and #333.
but it seems that these pull requests do not attempt to change behavior of the methods.

So I think this is a bug fix, not a breaking change.

of course, decent APIs are welcome.
I want standard method for getting bounding box to all ImageFont subclasses.

[aclark4life]

Thanks