Adds the Deque interface, and allows LinkedList to implement that interface.

This also changes ConcurrentLinkedQueue to implement the Queue interface, and just throw exceptions for operations which are not currently implemented.
Interfaces and the foundation for a ReentrantLock implementation
Add parkBlocker variable to Thread.java
Fix for travis build failure for needing to initialize the new field in Thread.
match Java's schizophrenic concept of inner class access modifiers

An inner class has two sets of modifier flags: one is declared in the
usual place in the class file and the other is part of the
InnerClasses attribute.  Not only is that redundant, but they can
contradict, and the VM can't just pick one and roll with it.  Instead,
Class.getModifiers must return the InnerClasses version, whereas
reflection must check the top-level version.  So even if
Class.getModifiers says the class is protected, it might still be
public for the purpose of reflection depending on what the
InnerClasses attribute says.  Crazy?  Yes.
Merge pull request #192 from dicej/inner-class-modifiers

match Java's schizophrenic concept of inner class access modifiers
Merge pull request #189 from jentfoo/interface_improvements

interface improvements and LockSupport implementation