Fix heading level of 'Try' section

It was agreed to be '## Try:' but there were many files where it was
'### Try:'. This has been corrected.

2013/birken/README.md

@@ -20,7 +20,7 @@ before it finishes) try using `reset` to restore the terminal. This will clear
 the screen.
 
 
-### Try:
+## Try:
 
 This alternate version, which we recommend that you use in order to see what is
 happening with modern systems, and to not flash colours too quickly, which can

2013/cable1/README.md

@@ -12,7 +12,7 @@ make
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2013/cable2/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2013 cable2 in bugs.md](/bugs.md#2013-cable2)
 ```
 
 
-### Try:
+## Try:
 
 For different OCR examples:
 

2013/cable3/README.md

@@ -15,7 +15,7 @@ available. See the [Alternate code](#alternate-code) section below.
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./runme

2013/dlowe/README.md

@@ -25,7 +25,7 @@ For more detailed information see [2013 dlowe in bugs.md](/bugs.md#2013-dlowe).
 where `[number...]` is one or more number, space separated.
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2013/endoh1/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2013 endoh1 in bugs.md](/bugs.md#2013-endoh1)
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh

2013/endoh2/README.md

@@ -21,7 +21,7 @@ you have both and if either is not found it will report it and tell you where to
 download one or both before exiting.
 
 
-### Try:
+## Try:
 
 ```sh
 cat jpeg.c

2013/endoh3/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2013 endoh3 in bugs.md](/bugs.md#2013-endoh3)
 ```
 
 
-### Try:
+## Try:
 
 Trying this out will depend on how your system can play sounds. The author's
 remarks include some options for different operating systems.

2013/endoh4/README.md

@@ -17,7 +17,7 @@ as recommended by the author. If no file is specified in `run.sh` command line
 it will feed to the program [endoh4.c](endoh4.c).
 
 
-### Try:
+## Try:
 
 ```sh
 ./run.sh cube.txt

2013/hou/README.md

@@ -27,7 +27,7 @@ image viewer ready.  Refresh the image every time the output refreshes, all
 effects should be more or less recognizable when you see 16.
 
 
-### Try:
+## Try:
 
 ```sh
 ./hou BIG

2013/mills/README.md

@@ -23,7 +23,7 @@ For more detailed information see [2013 mills in bugs.md](/bugs.md#2013-mills).
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./mills &

2013/misaka/README.md

@@ -16,7 +16,7 @@ information on all of these builds.
 ```
 
 
-### Try:
+## Try:
 
 To understand the various intermediate source files that are built, try:
 

2013/morgan1/README.md

@@ -12,7 +12,7 @@ echo "2013/10/03" | ./morgan1
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 echo "1985/10/28" | ./morgan1

2013/robison/README.md

@@ -15,7 +15,7 @@ echo expression | ./robison
 ```
 
 
-### Try:
+## Try:
 
 ```sh
 ./try.sh