Transport: Raise bandwidth refiller thread priority

so I/O doesn't stall under high CPU load
- Raise DH generator thread priority to keep
  DH building out of event pumper thread
- Raise PRNG and YK generator thread priorites one notch
- Set I2PThread priority in constructor
Fixes problems mainly seen on Windows, which seems
to be much more sensitive to priority settings

core/java/src/gnu/crypto/prng/AsyncFortunaStandalone.java

@@ -56,7 +56,7 @@ public class AsyncFortunaStandalone extends FortunaStandalone implements Runnabl
         _isRunning = true;
         _refillThread = new I2PThread(this, "PRNG");
         _refillThread.setDaemon(true);
-        _refillThread.setPriority(Thread.MIN_PRIORITY+1);
+        _refillThread.setPriority(Thread.NORM_PRIORITY - 2);
         _refillThread.start();
     }
 

core/java/src/net/i2p/crypto/YKGenerator.java

@@ -91,7 +91,7 @@ class YKGenerator {
             return;
         _precalcThread = new I2PThread(new YKPrecalcRunner(MIN_NUM_BUILDERS, MAX_NUM_BUILDERS),
                                        "YK Precalc", true);
-        _precalcThread.setPriority(Thread.MIN_PRIORITY);
+        _precalcThread.setPriority(Thread.NORM_PRIORITY - 2);
         _isRunning = true;
         _precalcThread.start();
     }

core/java/src/net/i2p/util/I2PThread.java

@@ -17,6 +17,8 @@ import java.util.concurrent.CopyOnWriteArraySet;
  * In case its useful later...
  * (e.g. w/ native programatic thread dumping, etc)
  *
+ * As of 0.9.21, I2PThreads are initialized to NORM_PRIORITY
+ * (not the priority of the creating thread).
  */
 public class I2PThread extends Thread {
     /**
@@ -31,36 +33,42 @@ public class I2PThread extends Thread {
 
     public I2PThread() {
         super();
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }
 
     public I2PThread(String name) {
         super(name);
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }
 
     public I2PThread(Runnable r) {
         super(r);
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }
 
     public I2PThread(Runnable r, String name) {
         super(r, name);
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }
     public I2PThread(Runnable r, String name, boolean isDaemon) {
         super(r, name);
 	setDaemon(isDaemon);
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }
     
     public I2PThread(ThreadGroup g, Runnable r) {
         super(g, r);
+        setPriority(NORM_PRIORITY);
         //if ( (_log == null) || (_log.shouldLog(Log.DEBUG)) )
         //    _createdBy = new Exception("Created by");
     }