Merge pull request #193 from nierob/master

Partial fix compilation on Windows.
Fix the build with MSVC

MSVC does not behave nicely with multi-line QStringLiterals so
use QLatin1Strings with string builder.
Another attempt to improve WebSocket handshake reply handling
Merge pull request #194 from bbandix/master

Fix the build with MSVC
Possible fix flakiness tst_EnginioModel::createAndModify

It is a guess, but it may happen that the network reply is marked as
finished and QTRY_VERIFY checks the value before finished signal is
emitted.
Fix flakiness of tst_EnginioModel::append()

EnginioReply::isFinished may return true before the finished signal is
emitted. That happens almost always when finished signal is delayed.