Review the code and implement OneToOneMap
*Eliminate the race conditions in Master.java as HashMap was shared by
different threads.
*Seperate interface to implementation in Master.java as Map is used
regardless of its implementation.
*Remove the NodeType in AbstractNode.java as AbstractNode is an abstract
class and no object can be instantiated. Its subclass indicates the
actual node type of itself. Therefore the NodeType information in
AbstractNode is redundant.
*Implement OneToOneMap data structure as there is a one-to-one mapping
relationship between node name and node URI.
Merge branch 'week8-demo' of https://github.com/cmusv-sc/Practicum2014-Ericsson-Media.git into week8-demo