Add ReadMe for virtualenv instructions

Author: mdmintz

help_docs/virtualenv_instructions.md

@@ -0,0 +1,40 @@
+### Virtual Environment Setup Instructions
+
+Mac: (If you're using virtualenv):
+
+```bash
+mkdir -p ~/Envs
+virtualenv ~/Envs/seleniumbase
+source ~/Envs/seleniumbase/bin/activate
+```
+
+Mac: (If you're using virtualenvwrapper):
+
+```bash
+mkvirtualenv seleniumbase
+```
+
+Windows:
+
+Use the "virtualenv" version above instead of "mkvirtualenv", but also make the following changes:
+1: Don't use "-p"
+2: Replace "~/" from above with the location of your home directory
+3: Instead of using the "source" command, go into the folder created and type ``activate``
+
+If you ever need to leave your virtual environment, use the following command:
+
+```bash
+deactivate
+```
+
+You can always jump back in later:
+
+(If you're using virtualenv):
+```bash
+source ~/Envs/seleniumbase/bin/activate
+```
+
+(If you're using virtualenvwrapper):
+```bash
+workon seleniumbase
+```