Added `function_invoker` which allows lambdas returning void to work.
Merge remote-tracking branch 'remotes/origin/function_invoke'
Fixed problem with templates shadowing.
I wonder if we could reuse template parameters of the outer class.
Added new test for lambdas; we really need better coverage.
Fixed noexcept problems on Visual Studio
Updated boost to 1.53 on Travis.
Merge pull request #13 from lundiorg/function_invoke

Function invoke