Added 2 unit test projects

- Corrected output path to contain full project names
- Deleted obsolete post build tasks what were responsible to copy LibGit2Sharp native binaries to the output folder. It is implemented now via build property: LibGit2Sharp.props
- Corrected default namespace in Wpf project: SolutionGenerator -> SolutionGenerator.Wpf
- Namespace WPF refactored to Wpf
- Corrected inconsistencies mixed using SolutionGenerator.Frontend.Wpf and SolutionGenerator.Wpf naming