Cleaned up the constructors, made some cosmetic changes, deque is now
compliant with uniform initialization, removed some useless typing on =
operators, removed assign member functions from darray and dllist,
added the some of the interface specifications for tree.
 On branch master
 Changes to be committed:
	modified:   darray.cpp
	modified:   darray.hpp
	modified:   deque.cpp
	modified:   deque.hpp
	modified:   dllist.cpp
	modified:   dllist.hpp
	modified:   node.hpp
	modified:   tree.hpp