Update  Zeppelin home page

Fix typo and misspelling.

# before
![screen shot 2014-10-11 at 4 33 24 pm](https://cloud.githubusercontent.com/assets/3139557/4601837/4ced6786-5119-11e4-9292-57e884245e55.png)

# After
![screen shot 2014-10-11 at 4 33 34 pm](https://cloud.githubusercontent.com/assets/3139557/4601839/50caf85a-5119-11e4-8850-f0bb8d7076a5.png)