ExcelWriter
Been trying to use ExcelWriter and getting the error:
writer = pd.ExcelWriter(filename) 
"  File "C:\Anaconda\lib\site-packages\pandas\io\excel.py", line 350, in **init**
    from openpyxl.workbook import Workbook
ImportError: No module named openpyxl.workbook"

I'm using Python 2.7 and updated Pandas to 0.12.0
