BUG: Fix dtypes order when ordering is different from original file in pandas.io.stata.read_stata
This fixes http://stackoverflow.com/questions/31783392/pandas-adding-columns-to-filter-will-mess-with-data-structure
The dtypes of the DataFrame returned by `read_stata` have the same order as the original stata file, even if `columns` are specified with a different order. 

looks good.
- minor code change
- pls add a note in whatsnew (use this PR number)
- squash
 Done, I got rid of the `matched` dict as well because it doesn't do anything.
 lgtm

pls rebase and squash (FYI move the release note higher up in the bug fix list and you wont get conflicts)
 Is this right? Looks like I screwed up something
 git help here: http://pandas.pydata.org/pandas-docs/stable/contributing.html

basically do

got rebase -i origin/master
 Right, well I pretty much did that. How does the PR look?
 did you `git push <username> <branchname> -f`. You have 16 commits here. You should have 1.
 This is a mess, I'm just going to open a new PR for this
