add Try section to recently updated README.md files

2018/algmyr/README.md

@@ -13,6 +13,8 @@ Twitter: @aalgmyr
     ./prog <file1> <file2> > out.raw
     ./prog -d 2 0 out.raw         # Decode the first (0th) channel out of two
 
+### Try:
+
     ./prog -h | ./prog -d 1 0
 
     # Who needs cat?

2018/anderson/README.md

@@ -10,6 +10,8 @@ Derek Anderson
 
     ./prog < textfile
 
+### Try:
+
     ./prog < prog.c
     ./prog < prog.alt.c
     ./prog < README.md

2018/bellard/README.md

@@ -11,6 +11,8 @@ Fabrice Bellard
 
     ./prog > lena.ppm
 
+### Try:
+
     eog lena.ppm # On Linux
     preview lena.ppm # On MacOS