Fix (hopefully) library dependency resolution.

Installing libs is now enabled, hardcoded.
Enable -Wall for all builds.
Fix many warnings and latent bugs.

logic/JavaChecker.h

@@ -17,7 +17,7 @@ class JavaChecker : public QObject
 	Q_OBJECT
 public:
 	explicit JavaChecker(QObject *parent = 0);
-	int performCheck(QString path);
+	void performCheck(QString path);
 
 signals:
 	void checkFinished(JavaCheckResult result);