rootcint.cxx: For non-prefix build, rootcint uses its location to
determine ROOTSYS, now also on windows. Fixes ROOTSYS for rootcint_tmp.

TWinNTSystem.cxx: add a registry entry such that double clicking .root
files starts root and opens the file. Also sets icon and title for .root-files.

$ROOTSYS/etc/fileopen.C can be customized; currently it simply opens a
TBrowser. The registry is only touched if $ROOTSYS/macros/fileopen.C exists.


git-svn-id: http://root.cern.ch/svn/root/trunk@23972 27541ba8-7e3a-0410-8455-c3a389f83636

git-svn-id: http://root.cern.ch/svn/root/trunk@19824 27541ba8-7e3a-0410-8455-c3a389f83636

git-svn-id: http://root.cern.ch/svn/root/trunk@11551 27541ba8-7e3a-0410-8455-c3a389f83636

macro and not a tutorial.


git-svn-id: http://root.cern.ch/svn/root/trunk@6379 27541ba8-7e3a-0410-8455-c3a389f83636

git-svn-id: http://root.cern.ch/svn/root/trunk@112 27541ba8-7e3a-0410-8455-c3a389f83636

git-svn-id: http://root.cern.ch/svn/root/trunk@81 27541ba8-7e3a-0410-8455-c3a389f83636

which included commits to RCS files with non-trunk default branches.


git-svn-id: http://root.cern.ch/svn/root/trunk@3 27541ba8-7e3a-0410-8455-c3a389f83636