Add getters and setters examples.
Add data types with examples.
Add examples of methods to work with NSSets.

Add note of NSSets being unordered.

Remove for loop to iterate on NSSet. Moved for loop to loop section.
spelling fixes in bash (en)
Added call, apply, bind JavaScript examples
Fix typos and indentation
Source.fromPath no longer exists (https://github.com/scala/scala/blob/master/src/library/scala/io/Source.scala)  Changed example to use Source.fromFile
Fix some comments to be more clear.
Add more data type examples.

Add NSMutableSet examples.
Add instance variable definition examples.