Added env variable way to output to stdout and autocheck for Jupyter

[gjvnq]

Basically, icecream will now automatically output to stdout if any of the following is true:

1. The environment variable PYTHON_ICECREAM_USE_STDOUT evaluates to true.
2. The code is running from inside Jupyter.

[gruns]

thank you for this PR!

why use stdout over stderr inside jupyter?

[gjvnq]

Because stderr shows in a different background color that makes it look like an error or warning.

…

On Sun, 9 Jan 2022 at 00:59, Ansgar Grunseid ***@***.***> wrote: thank you for this PR! why use stdout over stderr inside jupyter? — Reply to this email directly, view it on GitHub <#112 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAXIYHEPUI2GCEJXQGDLM43UVEB3PANCNFSM5KKS7M7Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[alexmojaki]

Related discussion: #77 (comment)

@gjvnq Why not use the isnotebook you put there? IPython is a lot more general than Jupyter notebooks.

Another way to detect Jupyter is described here: #100 (comment)

Apparently disabling colorama in Jupyter would be good too.

On another note, PYTHON_ICECREAM_USE_STDOUT is very wordy for a library all about convenience. IC_STDOUT seems sufficiently unique.