Merge pull request #5 from nerdinand/master

! fix warning: ignoring return value of function declared with const att...
Multithreading is not turned on by default anymore
Wrote exception class and macros for defining exceptions
Exceptions should be working
Fixed up unit tests
Resolving merge conflicts.
Removed some warnings about extra semi-colons
Unit tests take into consideration exceptions or assertions are enabled
Support for getting a pointer to a component rather than a reference
Getting a pointer to a system is now possible
Support for polymorphic systems
Updated readme
Method for checking if a system exists or not
Fixing const correctness
Name demangling of types when printing to the console
Added support for entities to request being configured by systems
Fixed chaining when configuring systems
Fixed an issue where a derived system couldn't declare configureEntity() private without breaking
! fix warning about reaching end of non-void function