Update README.md

Author: vadimkantorov

README.md

@@ -56,7 +56,9 @@ Feel free to copy-paste and run the examples above. More runnable examples are i
 
 # Building from source
 **mpegflow** depends only on a recent FFmpeg, **vis** depends on FFmpeg, OpenCV and libpng. The tools are known to work with FFmpeg 3.1 and OpenCV 3.1. You may use [wigwam](http://wigwam.in) to install them to a local directory (no root required):
-```wigwam init && wigwam install opencv ffmpeg```
+```shell
+wigwam init && wigwam install opencv ffmpeg
+```
 
 You will probably end up with a shared build, for static build, please feel free to play with Makefile.
 
@@ -74,8 +76,9 @@ To build the tools on Windows:
 4. Extract this OpenCV build to the `dependencies` directory using 7zip (for vis): https://github.com/opencv/opencv/releases/download/3.1.0/opencv-3.1.0.exe
 5. Open VS2015 x64 Native Tools Command Prompt (VS2015 Community Edition will work) and run:
 
-   ```shell
+```shell
 nmake mpegflow.exe FFMPEG_DIR=dependencies\ffmpeg-3.0.1-win64-dev\ffmpeg-3.0.1-win64-dev
 # nmake vis.exe OPENCV_DIR=dependencies\opencv-3.1.0\opencv\build\x64\vc14
 ```
+
 6. The Windows build is not fully static. You need to keep `avutil-54.dll`, `avformat-56.dll`, `avcodec-56.dll`, `swresample-2.dll` (for **mpegflow**) and `opencv_world310.dll` (for **vis**) in the same directory as the binary. Note that the instructions and the Makefile assume x64 machine architecture.