Autotools: Modernize

* Use pragma once
* Make sure overrides are everywhere
* Clean up code here and there
* Remove useless code from initializer lists

Change-Id: I9c285a803ea36cb32d14b3335757fd4b57f27d02
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/autotoolsprojectmanager/autotoolsprojectplugin.cpp

@@ -39,13 +39,8 @@
 
 using namespace AutotoolsProjectManager::Internal;
 
-AutotoolsProjectPlugin::AutotoolsProjectPlugin()
-{
-}
-
 void AutotoolsProjectPlugin::extensionsInitialized()
-{
-}
+{ }
 
 bool AutotoolsProjectPlugin::initialize(const QStringList &arguments,
                                         QString *errorString)