java-decompiler: fixes and cleanups

- console decompiler: resource closing, lookup instead of scan, error reporting
- logger interface reworked
- saver interface renamed
- bytecode provider returns byte array (to reduce stream leakage)
- extra level of context unit avoided
- unneeded exceptions, dead code, formatting

src/org/jetbrains/java/decompiler/main/rels/ClassWrapper.java

@@ -106,7 +106,7 @@ public class ClassWrapper {
 
               if (System.currentTimeMillis() >= stopAt) {
                 String message = "Processing time limit exceeded for method " + mt.getName() + ", execution interrupted.";
-                DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.ERROR);
+                DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.Severity.ERROR);
                 killThread(mtthread);
                 isError = true;
                 break;