updated ssao shader to be a hemispherical based

ambient occlusion shader; (hbao; uses normal G-Buffer and poisson disk
sample) added information key to represent outline meshes (to
differentiate in shader), added subclass of vtkShaderProgram2 to access
shader ID, added noise and normal textures to fbo in processing pass,
created custom depth peeling pass class, created advanced pass class
(for custom passes), cleaned up normal_buffer in smoothNormals method to
avoid memory leaks,  added GLEW (if required) - might remove, added
default values to uniforms in shader, updated bloom shader, fixed
regular lighting shader to use negated normals for inside-facing
polygons, physically based shader kept the same. screenshots updated,
created manual reset clipping plane method to stop vtk from
auto-computing clipping planes, deleted thread manager in main to avoid
memory leaks, /Zo for optimized visual studio release with debug info
debugging build, updated c++>debugging variable to modify environment
variable, path according to build.