Changes:
* Fix a collision of the name PS_NONE with a different constant in shlobj.h
* Update solution and project files for VS2013
* Update the NSIS installer to reference the VC 2013 redistributable
Make new versioned nmap.rc.in and nsis/Nmap.nsi.in, and use those to
generate unversioned nmap.rc and nsis/Nmap.nsi. The changes made to
those files were constantly causing problems with updating.