Please explain: why changed to markdown?
In https://github.com/pydata/pandas/commit/0bc568fb5e19208b30255d771dbf08552f47a4ba#diff-04c6e90faac2675aa89e2176d2eec7d8
 you changed to markdown.

Why?
It had stopped to daily Ubuntu builds. So I am just interested in the reason. 
After a short explanation, you may close here.

Thanks.
