Added missing files to Cake.CoreCLR.nuspec.
Added missing files to Cake.CoreCLR.nuspec.

Closes #1237

devlead/cake,patriksvensson/cake,daveaglick/cake,vlesierse/cake,gep13/cake,cake-build/cake,ferventcoder/cake,phenixdotnet/cake,mholo65/cake,phrusher/cake,vlesierse/cake,daveaglick/cake,mholo65/cake,adamhathcock/cake,Julien-Mialon/cake,patriksvensson/cake,cake-build/cake,devlead/cake,robgha01/cake,Sam13/cake,phrusher/cake,Julien-Mialon/cake,RehanSaeed/cake,adamhathcock/cake,Sam13/cake,thomaslevesque/cake,thomaslevesque/cake,gep13/cake,RehanSaeed/cake,phenixdotnet/cake,DixonD-git/cake,robgha01/cake,ferventcoder/cake