Merge branch 'web-request'

Add wxWebViewRequest and related classes allowing to use HTTPS and
HTTP/2.

See https://github.com/wxWidgets/wxWidgets/pull/977

tests/test.bkl

@@ -70,6 +70,7 @@
             misc/typeinfotest.cpp
             net/ipc.cpp
             net/socket.cpp
+            net/webrequest.cpp
             regex/regextest.cpp
             regex/wxregextest.cpp
             scopeguard/scopeguardtest.cpp