Adding WebEngineWrapper

This plugin is intended to be used with PyQt5, as it doesn't expose the
QtWebEngine class yet (last tested with PyQt5 version
5.4-snapshot-837edec02d98). Note you don't need to use it on a plain c++
program.

Signed-off-by: Rodrigo Oliveira <rodrigo@simb.com.br>
Adding simple python example

You need to export QML2_IMPORT_PATH pointing to the compiled plugin directory.
Refer to the README file for detailed instructions.

Signed-off-by: Rodrigo Oliveira <rodrigo@simb.com.br>