add separator parameter

[manelclos]

The previewer is trying to use "," as separator when it should use ";". Is there a way to specify this in the URL??

[RouxRC]

+10
I don't have any stats but there are so many CSV files using tabulations, ; or others separators that it would seem quite standard to first check the opened csv and try successively the different possible separators to find the one where all lines have the same number of columns. This would make the preview of ckan work in so many more cases I believe this is quite an urgent matter! :)

[rufuspollock]

In a perfect world i'd like to merge this with datapipes (https://github.com/okfn/datapipes) which does support a bunch of this ...

Hmmm - perhaps we can add a dataproxy style support there.

Basically, the blocker on work here is #5 - converting to flask.