This factors in distorted latitudes when calculating distances.

I noticed that some of the simplifications still made no sense and this was the
reason for it: at a longitude of 50 degrees, one degree of latitude attributes
to 64% Euclidean distance (whereas 1 degree of longitude always yields 100%).
I used Math.cos only once at the middle of the geometry, so results can be bad
at the north and south pole!!!! AND FOR CONTINENTS!!!
Re-used escapeRegex from $ui.autocomplete.
Discarded experimental messages option from autocomplete.
Improved autocomplete to use text input as regular expression.

The previous approach was kind-of half-baked because it completed to regular
expressions (i.e. escaped labels) but did not match against them.
Now anything typed in the text input will be treated as reqular expression and
I can see instantly if I made a mistake and what the filter results are.