Overlap proportion is not correct

[raacampbell]

I have at various times noticed that the requested overlap and the resulting overlap are not the same. e.g. I have found that I ask for a 5% overlap but that I see black lines between tiles if I crop by more 2%. So the way the overlap is calculated seems not right. This isn't really an important issue, but it's annoying that it's not right.

see ./components/@recipe/tilePattern.m seems like this can only be wrong if the FOV is calculated incorrectly.