Bump Touch.Unit.

New commits in spouliot/Touch.Unit:

* xamarin/Touch.Unit@e5a46fd [TouchRunner] Rename TestElement.Update to TestElement.TestFinished to make it clearer when it's used. (dotnet#73)
* xamarin/Touch.Unit@f8d9a21 [TouchRunner] Fix running multiple test assemblies in NUnitLite mode. (dotnet#76)
* xamarin/Touch.Unit@c151a18 [TouchRunner] Print test output to the console. (dotnet#75)
* xamarin/Touch.Unit@74fbc3f [TouchRunner] Keep track of the last shown test suite, and return to it when the app is relaunched. (dotnet#74)
* xamarin/Touch.Unit@857c584 [TouchRunner] Only update the UI for a single test after the test has finished running. (dotnet#72)
* xamarin/Touch.Unit@85f716d [TouchRunner] Fix unused variable warning by only defining the variable when it's used. (dotnet#71)
* xamarin/Touch.Unit@8bea179 [TouchRunner] Always show 'Run all'. (dotnet#70)
* xamarin/Touch.Unit@2c2a55e Move every Touch.Client projects to its own folder. (dotnet#69)
* xamarin/Touch.Unit@09733ed [TouchRunner] Improve name printing in NuGet mode. (dotnet#68)
* xamarin/Touch.Unit@8f2d02e Ignore any 'packages' directory. (dotnet#67)

Diff: https://github.com/spouliot/Touch.Unit/compare/b4e8606a85255f2456b0b20d5a0732298fa1ad36..e5a46fd0a05b3c3c84a0ba013463e957311db6f2