RegistryKeyMock can create subkeys.
Implemented RegistryMock.SetValue() method.
Implemented OpenSubKey() overload with writable parameter.
Implemented deletion of sub keys.
Implemented DeleteSubTree() method
Coverage settings for dotCover.
Enabled SystemMock assembly signing.
Version bump to v0.2.0
Configured project for NuGet packaging.
Merge branch 'release/NuGetPackage' into develop

* release/NuGetPackage:
  Configured project for NuGet packaging.
  Version bump to v0.2.0
  Enabled SystemMock assembly signing.
Merge branch 'release/NuGetPackage'

* release/NuGetPackage:
  Configured project for NuGet packaging.
  Version bump to v0.2.0
  Enabled SystemMock assembly signing.
AppVeyor will build all branches. Added badges.
Merge branch 'develop'

* develop:
  AppVeyor will build all branches. Added badges.