inlineEditor no longer calculates the dirty state on every single key

press. Instead, it calculates it at most once every 200ms. This helps to

improve performance when the text field is large.
When it does calculate, the default behavior is now to first compare the

lengths of the strings. If those differ, then there's no need to compare

the string contents.

Tested this along with some other changes. The performance felt a lot nicer.
console.time says that the calculations only took about 0.01ms on average

for a medium-sized text field. However, along with other operations that may be

performed based on changes, and the draw times needed for the text display (when

using CodeMirror), this does appear to contribute to a noticeable difference.
(The defer may be a large part of it, but the throttling seems to help... I'm

guessing more is going on than console.time is telling us.)