This fixes a problem introduced in
c7b31b0242.
The changes by @tobibeer inadvertently made the regular expression
evaluation significantly more expensive because of lookahead. The is
less elegant but reverts the performance problem.
Ok, I think I've got it now. The following matches all...
1. starting with a literal `$:`
2. then any number of character not a whitespace, `<` or `|`
3. closing with anything that is, again, not a whitespace, `<` or `|`
Test here...
http://tbdemo.tiddlyspot.com/#Autolink%20System%20Tiddlers
