Remove test main() method in Register.java
Remove two unused variables in DADDU.java

Also add a simple unit test for DADDU.
Remove two unused variables in DSUBU.java

Also add a simple unit test for DSUBU.
Remove test main() method in Loading.java
Remove unused variable in ErrorDialog.java
Remove useless postincrement operation in GUICode.java
Remove unused variable in GUICycles.java
Merge pull request #56 from GraziaCiraulo/master

Coverity Scan fixes.