Deprecate detection of IPython frontends

[takluyver]

The check for the Qt console won't be necessary in IPython 3 and above: we decided that the Qt console's display of HTML reprs was so bad that it shouldn't attempt to show them. We also want to remove the parent_appname config value (ipython/ipython#4980), which will break both of these functions (making them always return False).

The assignment to ipnbh was redundant - nothing used that variable. I guess it was used previously and didn't get cleaned up during some changes (quite possibly my own omission).

[jorisvandenbossche]

About the qtconsole, then this issue #7372 can maybe closed? (which is a nice illustration of how bad it can be ...)

[takluyver]

I've rebased this pull request - I think it's ready for review.

[jreback]

is their a min ipython version that this requires? (we don't test this per se), e.g. will this break with an older version of ipython but pandas 0.14.1/master?

[takluyver]

I've not actually changed anything functionally (the assignment I removed is an unused variable), so no, it won't break.

When IPython 3.0 has been out for a while, I'll make another PR to remove this code. This deprecation is just to ensure pandas doesn't start using this functionality for anything new while we're removing it.

[jreback]

so if someone uses ipython 0.11 it will still work the same?

[takluyver]

Yes - this PR should not change how anything actually works whatsoever. All it does is:

• Add deprecation notes in comments and docstrings
• Remove an assignment to an unused variable

[jreback]

thanks!