Make vboot_reference build in MSVC command line environment.

msc/README.txt

+This directory contains the Microsoft Visual C makefile for building vboot
+reference code (and testing, eventually) in a 32 bit DOS window.
+
+Microsoft Visual C 2008 (or later) is the prerequisite for this to work.
+
+To build vboot_reference tree in the DOS window do the following:
+
+- untar or git clone the vboot_reference source tree
+
+- open a DOS window
+
+- run the MSVC provided script vcvars32.bat to create the command line build
+  environment. Script location is MSVC installation specific. For instance:
+
+  c:\> \bios\devtls\MSVC9\Vc\bin\vcvars32.bat
+
+- define a directory where the nmake output should go into
+
+  c:\> set MOD=z:\shared\tmp
+
+- start the make job as follows:
+
+ c:\> nmake /f %path_to_vboot_reference_tree%\msc\nmakefile
+
+- observe the output generated in %MOD%