#1 User preference for hit testing links

[Neil Earnshaw]

Hit testing on links is managed in the DKPath class. The
critical line is

if \( \[self hitTest:m

againstLineFrom:[fromDKPoint nsPoint]
to:[toDKPoint nsPoint]
allowedDistance:2.0] )
return YES;

allowedDistance is hard coded, and the value of 2.0 causes
problems for some screen resolutions and some users.

The allowedDistance should be a User Preference in the
range 5.0 to 2.0.