[m-rev.] diff: update MSVC README

[Julien Fischer]

Update MSVC README.

README.MS-VisualC.md:
      It is no longer necessary to set up file copying in the post-installation
      step to have a version of the Mercury compiler using MSVC that works on
      the Windows command prompt. The configuration script now chooses to
      use internal file copying by default when using MSVC.

Julien.

diff --git a/README.MS-VisualC.md b/README.MS-VisualC.md
index c76ea10..c226a17 100644
--- a/README.MS-VisualC.md
+++ b/README.MS-VisualC.md
@@ -179,13 +179,6 @@ installation. (In future releases, this will all hopefully be automated.)
  All references to files in the following are within the Mercury installation
  directory

-* By default, the Mercury compiler will attempt to use the `cp` command to
-  install files. Since Windows does not provide this, you will need to provide
-  an alternative (see the next section for details of how to do this).
-
-  We recommend installing the [UnxUtils](https://sourceforge.net/projects/unxutils/)
-  port of `cp` and using that with Mercury.
-
  * In the file `lib/mercury/conf/Mercury.config`:

    + Replace any Unix-style paths with their Windows-style equivalent. 
@@ -197,15 +190,6 @@ directory
          --host-env-type "windows"
          --target-env-type "windows"

-  + To specify the commands used to install files and directories include
-    the following options in the value of the variable `DEFAULT_MCFLAGS`
- 
-        --install-command <cp>
-        --install-command-dir-option <opt>
-
-    (NOTE: if you are using the UnxUtils port of `cp` then you don't need to
-    do anything here; the default settings will suffice.)
-
  * In the file `lib/mercury/mdb/mdbrc`

    + The backslash character, `\`, is used as an escape character in mdbrc