Fix including http:// in the proxy URL:
The proxy host parsed incorrectly, when it was typed with a scheme (http or https).
Now proxy can be specified with the scheme.

Fix invalid type conversion:
m_proxyPort converts to its ASCII representation.
Use `QString::number` to include a proxy port properly.

Issues:
https://github.com/ariya/phantomjs/issues/11117
https://github.com/ariya/phantomjs/issues/10811
Unit test: tweak secure connection check.

The main wikipedia page can be slow to load and thus triggers the timeout.
Let's use the fast Google site so that we don't get flaky outcome.

Issue #10882: https://github.com/ariya/phantomjs/issues/10882
Unit tests: terminate any web servers after finishing the tests.

Issue #11163: https://github.com/ariya/phantomjs/issues/11163
Issue #11243: https://github.com/ariya/phantomjs/issues/11243
Unit tests: robustify the tests of PDF, GIF, PNG, JPEG rendering.

Issue #10973 https://github.com/ariya/phantomjs/issues/10973