Update copyright, add default files and update versioning

 * Copyright updated to list 2013-2014, also updated to comply with StyleCop file header rule
 * Added default asset files (dk_disabled.png and tp_blank.png)
 * Added a versioning system, TeamCity will (hopefully) automatically populate the build part of the version
 * Major.Minor.Patch is handled manually in AssemblyVersion.cs and git tags