Drop QT4 from master

[Jean-Marc Lasgouttes]

Le 29/12/2020 à 09:42, Yuriy Skalko a écrit :
> Seems like boost::regex has the same issues as std::regex:
> https://www.boost.org/doc/libs/1_75_0/libs/regex/doc/html/boost_regex/unicode.html 
> 
> As I understand the ICU library is the only ultimate solution for 
> Unicode support.

Qt relies on ICU, it would be nice to be able to use the bundled library 
directly.

JMarc