Merge pull request #645 from elitest/hardfailvenv

Add a check to see if virtualenv is installed.

dev

@@ -2,7 +2,7 @@
 set -e
 VENV=../venv.mitmproxy
 
-python -m virtualenv $VENV
+python -m virtualenv $VENV || { echo 'virtualenv is not installed. Exiting.' ; exit 1; }
 source $VENV/bin/activate
 pip install --src .. -r requirements.txt
 

dev.bat

@@ -11,4 +11,4 @@ if %errorlevel% neq 0 exit /b %errorlevel%
 echo.
 echo * Created virtualenv environment in %VENV%.
 echo * Installed all dependencies into the virtualenv.
-echo * Activated virtualenv environment.
+echo * Activated virtualenv environment.