Adicionar suporte para o Framework 4.5

[bmgandre]

Tentei utilizar o docsbr em projeto com framework 4.5 obtive a seguinte mensagem de erro.

Could not install package 'docsbr 1.3.0'. You are trying to install this package into a project that targets '.NETFramework,Version=v4.5', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.