Update README to match EGSnrc web page
Update README to match EGSnrc web page

mchamberland/EGSnrc,mchamberland/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,nrc-cnrc/EGSnrc,mchamberland/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,crcrewso/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,nrc-cnrc/EGSnrc,mchamberland/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,crcrewso/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,mchamberland/EGSnrc