Merge pull request #58 from idan/master

Adding readme for idan theme

themes/idan/README.md

+## idan
+A functional, uncluttered fish theme with usability perks for git users and python developers.
+
+
+![Screenshot of idan theme](https://f.cloud.github.com/assets/22723/544512/14b7cd6e-c251-11e2-82c0-d5b4f41581c7.png)
+
+
+#### Characteristics
+
+##### Left Prompt
+
+* Current python virtualenv (if applicable)
+* Truncated CWD (just the current folder name)
+* Git branch and dirty state (if applicable)
+
+##### Right Prompt
+
+* Full CWD path
+* Last error code (if applicable)