Update singleton.h

Changing to Meyer's Singleton Implementation as it's also lazy initialized but simpler and thread-safe as stated on C++ standard since C++11 ( §6.7 [stmt.dcl] p4 ).
Update singleton.h

Fixing error created while changing to Meyer's Singleton Implementation.
Changing Variable Names

Changing variable names to follow the naming convention used.
Start working on third draft of Prototype.
Finish third draft of Prototype.
Link to blog on index.
Benchmark programs for Structure of Arrays.
Working on outline and code for structure of arrays.
Finish outline for Structure of Arrays.
Add link.
Start first draft of Structure of Arrays.
"Structure of Arrays" -> "Data Locality".
More work on first draft.
Got a bit more done.
More work on first draft of Data Locality.
More work on Data Locality.
Finish first draft of Data Locality.
Fix #35.

Make sure any class with a virtual method has a virtual dtor. Also a
few other cleanups.
Merge branch 'master' of https://github.com/TiagoRabello/game-programming-patterns into singleton

Conflicts:
	code/cpp/singleton.h
Tweak Singleton to explain static variable.