expand_tilde in pnd_utility now understands that ~ actually maps to the logged in...

expand_tilde in pnd_utility now understands that ~ actually maps to the logged in users homedir --
ie: In the event pndnotifyd is run as root from init/etc, and finds ~ in the dot-desktop emit path,
it should figure out tha actual user's homedir, not roots.

NOTE: This is for expand-tilde and not functions that depend on wordexp() -- ie: searchpaths, where
~ would be a standard shell expansion for the user who ran the job