Fix 'e' feature of 2015/burton + formatting

The program is supposed to echo stdin to stdout if the program name
starts with 'e'. This was only possible if one do something like:

    PATH=$PATH:.
    echo '5*5+17' | eprog

because otherwise the first char would be '.' not 'e'.

This was done by using basename(3) and -include libgen.h (in the
Makefile so as to not modify the code more than is necessary).

The Makefile now copies 'prog' to 'eprog' and 'prog' to 'calc'. It also
copies 'prog.alt' to 'eprog.alt' and 'ecalc.alt' as this is what the
program is documented as.

Format fix the calc.1 man page and remove calc.man. This is so that the
formatting is correct and also so as to not have to maintain more than
one copy of the same text (which was almost certainly already out of
sync as I did not update calc.man when I added calc.1 exactly for the
reason that I deleted calc.man).

The try.sh script has been updated and so has the try.this.txt file that
try.sh uses.

This should complete the review of 2015/burton if I'm not very much
mistaken.

thanks-for-help.md

@@ -3798,10 +3798,43 @@ output.
 
 ## <a name="2015_burton"></a>[2015/endoh3](/2015/burton/prog.c) ([README.md](/2015/burton/README.md]))
 
-[Cody](#cody) added the [try.sh](/2015/burton/try.sh) script. This involved
+
+[Cody](#cody) fixed the code so one can make use of the echo feature, where the
+first character of the filename starts with `e`. The only way it would work
+before that is if one did something like:
+
+```sh
+ln -sf prog eprog
+PATH=$PATH:. ; eprog '...'
+```
+
+since otherwise the first character would not be `e` but rather a dot
+(`./eprog`). This was done by adding to the Makefile `-include libgen.h` and
+adding to `main()` after the variable declaration (`V*A;`) the code:
+
+```c
+*K=basename(*K);
+```
+
+This was done for both the [prog.c](/2015/burton/prog.c) and
+[prog.alt.c](/2015/burton/prog.alt.c). The Makefile was also updated to build
+`eprog` and `eprog.alt` to make use of the feature more easily. Each is a new
+target (first in `TARGET` and second in `ALT_TARGET`) which have a prerequisite
+of `${PROG}` and `${PROG}.alt` respectively and which copies `prog` and
+`prog.alt` to `eprog` and `eprog.alt` respectively. With these changes now one
+can easily use the echo feature the author implemented.
+
+Cody also added the [try.sh](/2015/burton/try.sh) script. This involved
 adding a text file, [try.this.txt](/2015/burton/try.this.txt).
 
+Cody also added [calc.1](/2015/burton/calc.1) in place of `calc.man` to have
+proper formatting (in the style of `man(1)`). The `calc.man` was removed so as
+to not have to maintain two copies of the same text.
 
+Cody updated the Makefile to copy the `prog` to `calc` and `prog.alt` to
+`calc.alt`. `ecalc` and `ecalc.alt` also work. This is because the program is
+called `calc` and is in documentation including the man page. Thus one only need
+add a `./` to the commands in the man page/README.md.
 
 
 ## <a name="2015_dogon"></a>[2015/endoh3](/2015/dogon/prog.c) ([README.md](/2015/dogon/README.md]))