Added an example of per-project dependency management tool. Fixes #162.

Author: anenadic

_episodes/12-virtual-environments.md

@@ -63,10 +63,10 @@ which contains a particular version of Python installation
 plus a number of additional external libraries.
 
 Virtual environments are not just a feature of Python -
-most modern programming languages use them to isolate libraries for a specific project
+most modern programming languages use them to isolate libraries/dependencies for a specific project
 and make it easier to develop, run, test and share code with others.
-Even languages that don't explicitly have virtual environments have other mechanisms
-that promote per-project library collections.
+Even languages that do not explicitly have virtual environments have mechanisms
+that promote per-project dependency collections (e.g. Maven with classpath for Java).
 In this episode, we learn how to set up a virtual environment to develop our code
 and manage our external dependencies.