Using an invalid regex in the find panel causes a crash

[Tim Stack]

Problem

Entering an invalid regular expression in the find panel will cause a crash.

How to reproduce

1. Start tl with a file
2. Press / to open the find dialog
3. Enter *
4. Turn on the Regex checkbox
5. Press the the down arrow key

Expected

An error message should be shown and maybe the invalid part of the regex should be highlighted

Actual

tl crashes with a traceback and error: nothing to repeat at position 0

[Will McGugan]

Thanks. Should be fixed in 1.1.1