regex filter in DataFrame.filter
Hi pandas folks - 

Back to using pandas after having to take a hiatus in MATLAB.  One minor problem I ran into was the use of re.match instead of re.search (as is documented) in the DataFrame.filter method.   

I assumed there was a good reason for the change, but for most of my use cases the re.search way was less verbose.   

We should update the method documentation anyway, but could you see supporting both re.match and re.search?

Excellent package and am using in on a daily basis for both research and production code.

Best,

Elliott   
