Documentation improvements etc.

- Mention new feature in the SystemVerilog section in the README file
- Commented changes much better
- Rename a few signals to make it clearer
- Prevent warning for unused signals in an easier way
- Add myself as copyright holder to 2 files
- Fix one potential memory leak (delete 'wire' if not in modport)

kernel/rtlil.cc

@@ -639,11 +639,9 @@ RTLIL::Module::~Module()
 		delete it->second;
 }
 
-void RTLIL::Module::reprocess_module(RTLIL::Design *design, dict<RTLIL::IdString, RTLIL::Module *> local_interfaces)
+void RTLIL::Module::reprocess_module(RTLIL::Design *, dict<RTLIL::IdString, RTLIL::Module *>)
 {
 	log_error("Cannot reprocess_module module `%s' !\n", id2cstr(name));
-	(void)local_interfaces; // To remove build warning
-	(void)design;           // To remove build warning
 }
 
 RTLIL::IdString RTLIL::Module::derive(RTLIL::Design*, dict<RTLIL::IdString, RTLIL::Const>, bool mayfail)