Check whether the LaunchArguments are null before trying to format them.
Merge pull request #102 from rseanhall/bug4470

WIXBUG:4470 - LaunchArguments not optional when LaunchTarget is specified
Create path2utl for path functions that require shlwapi.lib.
Merge pull request #104 from rseanhall/bug4467

WIXBUG:4467 - Linker error on building C++ Custom Action Project