Implement wrapping search.
Add escapes for special regex characters.
Change to use set_sel() rather than indicators, to more closely math ta's
simple search behaviour.
Set the status bar text rather than using ui.print().
Implement backwards searching.
Don't include newlines in ".".  This also makes regexes including ".*"
more likely to work (avoiding the "too many pending choices/calls" LPEG
error).