Add DCL and Initializing on demand holder idiom.
add some references to class comments
Merge branch 'master' of https://github.com/mortezaadi/java-design-patterns into mortezaadi-master

Conflicts:
	singleton/src/main/java/com/iluwatar/App.java
Merge branch 'mortezaadi-master'
Merge branch 'master' of https://github.com/MSaifAsif/java-design-patterns into MSaifAsif-master
Merge branch 'MSaifAsif-master'
Fixed package name and some spelling mistakes.
Further cleanup of pom.xmls.
Improved comments for decorator example.
Improved decorator example.
Improved comments for the facade example.
Added unit tests for each of the patterns.
Merge pull request #1 from iluwatar/master

Updating master