chore(README.md): little fixes

README.md

@@ -9,13 +9,13 @@ Here are the general instructions to build linphone for desktop. The specific in
 1. Install some build tools: `CMake`, `Python` and `Qt5` (_5.8 or newer_).
 2. It's necessary to set the environment variable `Qt5_DIR` to point to the path containing the cmake folders of Qt5. Example:
 
-Qt5_DIR="~/Qt/5.9/gcc_64/lib/cmake/Qt5"
+        Qt5_DIR="~/Qt/5.9/gcc_64/lib/cmake/Qt5"
 
 3. The `PATH` environment variable must point to the Qt5 directory `bin`. Example:
 
-PATH="~/Qt/5.9/gcc_64/bin/:$PATH"
+        PATH="~/Qt/5.9/gcc_64/bin/:$PATH"
 
-4. Prepare the build by running the prepare.py script.
+4. Prepare the build by running the `prepare.py` script.
 5. Build the project using the appropriate build tool (`make`, `ninja`, `Xcode`, `Visual Studio (2013 or 2015 version)`).
 
 ## Specific instructions for the GNU/Linux and Mac OS X platforms