Add CMakeLists.txt and msvc_runtime.cmake.

- These files facilitate project/makefile generation.
- Remove old Visual Studio projects.
- Rename Makefile to Makefile.unix.

Change-Id: If786edd75d44c462538526c286eccc5cbf15d828

build/msvc_runtime.cmake

@@ -0,0 +1,24 @@
+##  Copyright (c) 2015 The WebM project authors. All Rights Reserved.
+##
+##  Use of this source code is governed by a BSD-style license
+##  that can be found in the LICENSE file in the root of the source
+##  tree. An additional intellectual property rights grant can be found
+##  in the file PATENTS.  All contributing project authors may
+##  be found in the AUTHORS file in the root of the source tree.
+cmake_minimum_required(VERSION 2.8)
+
+if(WIN32)
+  # CMake defaults to producing code linked to the DLL MSVC runtime. In libwebm
+  # static is typically desired. Force static code generation unless the user
+  # running CMake set MSVC_RUNTIME to dll.
+  if(NOT "${MSVC_RUNTIME}" STREQUAL "dll")
+    foreach(flag_var
+            CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+            CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+      if(${flag_var} MATCHES "/MD")
+        string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
+      endif(${flag_var} MATCHES "/MD")
+    endforeach(flag_var)
+  endif(NOT "${MSVC_RUNTIME}" STREQUAL "dll")
+endif(WIN32)
+