replace trailing whitespace with blackslash in README.md

As an alternative to the markdown trailing whitespace as a line
break, we use a trailing blackslash as a markdown line break.

2012/tromp/README.md

@@ -1,7 +1,7 @@
 # Most functional
 
-John Tromp  
-<john.tromp@gmail.com>  
+John Tromp\
+<john.tromp@gmail.com>\
 <http://tromp.github.io/>