add tool to sort .gitignore content

We sort with lines starting with # first.
We sort with lines starting with * second.
We sort with lines that do not start with [#!*] third.
We sort with lines starting with ! fourth.

Example usage in vim with a keyboard macro <escape>f:

```vim
:map ^[f 1G!G../../bin/sgi^M
```

 or via .vimrc:

```vimrc
" sort the entire .gitignore file using ../../bin/sgi
:map  ^[f 1G!G../../bin/sgi^M
```

 NOTE: The ^[ above is ((Escape)) and ^M is ((Control-M)).

Example usage in shell:

```sh
rm -f t && ../../bin/sgi < .gitignore > t && mv -f t .gitignore
```

Suggested usage:

```sh
bin/all-run.sh bin/sort.gitignore -v 1
```

Sorted all winner .gitignore according to this method.
Sorted all year level .gitignore according to this method.
Sorted top level .gitignore according to this method.

2011/akari/.gitignore

@@ -1,5 +1,6 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
+*.dSYM
 akari
 akari2 
 akari2.c
@@ -8,7 +9,6 @@ akari3.c
 akari4
 akari4.c
 akari.orig
-*.dSYM
 even_output.ppm
 expanded_and_rot13_output.txt
 expanded_output.txt

2011/blakely/.gitignore

@@ -1,8 +1,8 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
+*.dSYM
 blakely
 blakely.orig
-*.dSYM
 garden.txt
 indent
 indent.c

2011/borsanyi/.gitignore

@@ -1,8 +1,8 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
+*.dSYM
 borsanyi
 borsanyi.orig
-*.dSYM
 indent
 indent.c
 indent.o

2011/dlowe/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 dlowe
 dlowe.orig

2011/eastman/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 eastman
 eastman.orig

2011/fredriksson/.gitignore

@@ -1,8 +1,8 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
+*.dSYM
 ag
 ag.c
-*.dSYM
 fredriksson
 fredriksson.orig
 fredriksson.txt

2011/goren/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 goren
 goren.orig

2011/hamaji/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 dragon
 dragon2

2011/hou/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 hou
 hou.orig

2011/konno/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 indent
 indent.c

2011/richards/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 indent
 indent.c

2011/toledo/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 indent
 indent.c

2011/vik/.gitignore

@@ -1,8 +1,9 @@
-#
-# sort with: sort -d -u
-audio_file.raw
 
+#
+# sort with: ../../bin/sgi
 *.dSYM
+*.wav
+audio_file.raw
 indent
 indent.c
 indent.o
@@ -10,4 +11,3 @@ prog.orig
 vik
 vik.alt
 vik.orig
-*.wav

2011/zucker/.gitignore

@@ -1,5 +1,5 @@
 #
-# sort with: sort -d -u
+# sort with: ../../bin/sgi
 *.dSYM
 hello.ppm
 image2.ppm