Commented out SetupCallbacks under Think, as...

...the function is empty yet it's still called and tends to throw Lua Errors.
Updated self:SetupCallbacks() fix
Removed defunct Justin.TV Support (1/2)
Removed defunct Justin.TV Support (2/2)
Merge pull request #60 from WinterPhoenix96/master

Added a check for SetupCallbacks() validity in cl_html.lua/Removed Justin.TV Support, as it is now defunct