This is a copy and paste of videood. We should
factorize it in the future

Since the filename generation is based on the video.ext
field, we have to fill it before to check if the file
is downloaded.

Also do a little code factorisation

For windows compatibility

print is a function in Python 3
closes #1421

related to e93d724e

should close Debian Bug report logs - #772357

check python version
add Gpg4win installation

flake8 --select W391,E302,E301,E304

autopep8 can't fix W391 even though it claims it can.
Fixed using a simple custom script.

autopep8 -a -r -i --select E711,E712,W601,W602,W603,W604,W690,E304,E401,E502 .
Also includes some manual reindentations (many are left after the print()
changes).
Manually checked, some modernizations not commited here.

weboob.tools.browser -> weboob.deprecated.browser
weboob.tools.parsers -> weboob.deprecated.browser.parsers
weboob.tools.mech -> weboob.deprecated.mech
weboob.browser2 -> weboob.browser
weboob.core.exceptions -> weboob.exceptions

Also, the new tree for browser2 is:

weboob.browser: import weboob.browser.browsers.* and weboob.browser.url.*
weboob.browser.browsers: all browsers (including PagesBrowser and LoginBrowser)
weboob.browser.url: the URL class
weboob.browser.profiles: all Profile classes
weboob.browser.sessions: WeboobSession and FuturesSession
weboob.browser.cookies: that's a cookies thing
weboob.browser.pages: all Page and derivated classes, and Form class
weboob.browser.exceptions: specific browser exceptions
weboob.browser.elements: AbstractElement classes, and 'method' decorator
weboob.browser.filters.*: all filters

python modernize.py --no-six -f libmodernize.fixes.fix_print -w

With manual fixes as the import was put always on top.

Fixes #1355