Updated README

Removed todo list from readme
Fixed typo in CMakeLists

Fixed typo on filename for SphericalLight.hpp causing cmake generation to fail
Added c++11 to compiler flags

Explicitly set c++ standard for gcc compilers to c++11 so that advacned techniques used in the project like initializer lists and lambda's will compile without error
Changed name of Material accesor

Changed name of Material accessor for shapes to SurfaceMaterial to fix compile error of "changing type name"
Fixed compile error for Vector class

Fixed typo, initizlizer list, and added explicit header for Vector3D to Plane class definition to resolve compile errors. Vector3D class is used and must be fully defined to compile
Added missing semicolons
Added missing vector sources

Vector3D header and source were missing from project definition in CMake, added them in
Fixed incomplete definition of Vector3D

Vector3D is used in class definition and needs to be fully defined. Removed forward declaration and replaced with header include
Fixed typo

Fixed typo in Vector3D namespace
Changed default plane normal

Changed  default plane normal to [0 0 1]. Previous default normal was [0 0 0] which is not a valid normal.
Fixed two typos

Fixed typo in calling base class constructor and fixed typo in local variable in intersection computations
Fixed spacing and indentation
Added missing features to engine definition

Added missing screen, width and height functionality (accessors, etc). Refactored and cleaned up some code
Added threads member to engine

Added array to engine class for tracking background tracer threads.
Added sphericallight.cpp to cmakelists
Added missing const declarations to source

Some const markers were present in the header but missing in the source, added them back in for consistancy
Moved i/ostream to forward declarations

o/istream classes are only used by reference in the Vector3D header and therefore should be forward declared to reduce header complexity. This is accomplished by including the <iosfwd> header which correctly forward declares any ios classes, it is not considered correct to attempt these forward declarations yourself. Because iostream is no longer present, <initializer_list> is manually included in the header
Fixed missing const reference on weight function declaration
Various fixes to const correctness
Added missing const to definitions