nsis-installer: Use custom page for shortcuts and install for all users. * binary-dist-rules.mk: copy installer-files/README.html to dist folder. * installer-files/README.html: New file. * makeinst-script.sh: Added custom page for Install for all users and Create shortcuts. Reassigned show readme checkbox for showing README.html at end of install. Run octave-gui as the Run program.

## System-wide startup file for Octave.
##
## This file should contain any commands that should be executed each
## time Octave starts for every user at this site.
EXEC_PATH (cstrcat (fullfile (OCTAVE_HOME, 'notepad++'), pathsep, EXEC_PATH));
EXEC_PATH (cstrcat (fullfile (OCTAVE_HOME, 'bin'), pathsep, EXEC_PATH));
EDITOR (fullfile (OCTAVE_HOME, 'notepad++', 'notepad++.exe'));