Change default value of dupe_mangle_cols in read-table/csv to False

[ghost]

RELEASE.rst for 0.11.1 gave fair warning to users.

Update: there was no 0.11.1, it became 0.12.

[ghost]

@jreback , @cpcloud , 0.12?

[jreback]

0.13 for this

[jreback]

@y-p are we also going to raise on engine='python'? (the original csv writer, supposed to be removed in 0.13)

[ghost]

does this issue have anything to do with the old/new writer? In any case, I'm for keeping
"old reliable" around indefinitely. I think I closed that issue myself a while back.

[jreback]

no....i was just noticing it....(+1 on the old engine)..though maybe remove in 0.14...

[jreback]

This actually causes some issues when I change the default. Basically the structures are constructed as dicts, so that a non-unique column scheme causes failure in readback.

[ghost]

This has been around for a while and no one's asked for it. If we have to rewrite a bunch of stuff
to do it, and no one really cares -- Let's not.

[jreback]

gr8! this is a rabitt whole.....