build.sh not working if nuget.config present

[t081as]

If a nuget.config file containing a repository path is present the build.sh script is not working as expected since the cake executable is extracted to the wrong directory.

build.sh output:

Downloading packages.config...
Downloading NuGet...
Feeds used:
  https://api.nuget.org/v3/index.json

Restoring NuGet package Cake.0.30.0.
  GET https://api.nuget.org/v3-flatcontainer/cake/0.30.0/cake.0.30.0.nupkg
  OK https://api.nuget.org/v3-flatcontainer/cake/0.30.0/cake.0.30.0.nupkg 20ms
Installing Cake 0.30.0.
Adding package 'Cake.0.30.0' to folder '/builds/tobiaskoch/LinkTime/Build/Packages'
Added package 'Cake.0.30.0' to folder '/builds/tobiaskoch/LinkTime/Build/Packages'
Could not find Cake.exe at '/builds/tobiaskoch/LinkTime/Tools/Cake/Cake.exe'.

This happens due to a missing "-OutputDirectory" command line argument in the build.sh script (that is present in the build.ps1 script).

I've prepared pull request #64 to fix the issue.