Cleanup before migrating to git.
Removed uses of const non-reference return types.

A return type of const non-reference is useless since it can be freely
assigned to a non-const variable and then modified.
Fixed bug w/color base functions not being virtual
Removed unnecessary color parameter to textured lambertian constructor.
Removed some unnecessary inlines.
Converted tabs to spaces. What was I ever thinking?
Cleaned up intersection code in default acc.
Removed many shadowing warnings.