remove Python2 hybridation code

[a-detiste]

print() is available since Python 2.6

https://wiki.debian.org/Python3-six-removal

[a-detiste]

Thanks for the review

The right thing to do is to get rid of INTEGER_TYPES altogether:

-if type(commandTypeOrEvent) in INTEGER_TYPES:
+if isintance(commandTypeOrEvent, int):

[jmoraleda]

I agree with this PR. I also agree with removing all six usage.

[komoto48g]

I agree with dropping support for Python 2. IMHO, this PR is too aggressive and the first commit (removing print_) would be more acceptable if it was a separate PR.

From "https://wxpython.org/pages/contributor-guide/", 5. Do not put more than one fix/feature in the same branch or PR. Make a new distinct branch and PR for each of them.

[a-detiste]

I m on Holliday. Anyone can cherrypick the first commit that removes py2.6< compatibility if it tastes them, I ll redo this work in smaller pieces when I get back.

[a-detiste]

At first there was only this one first commit untill I got asked to proceed further

[newville]

Please merge.

[a-detiste]

The PR against GRASS (which uses Wx by the way) had a similar +/- size and went in smoothly. I m not scared. What do we need to go further ?