Character that grows the string when lowercased.

[buckett]

Unicode has special rules about lowercasing characters http://www.unicode.org/Public/UNIDATA/SpecialCasing.txt and this can result in a string growing. When doing the reverse the strings don't appear to shrink (Java/Python). You can see python 3 growing the strings when lowercasing:

>>> len("İ")
1
>>> len("İ".lower())
2

[buckett]

Shout out to @davbo for starting this with #127