New built-in commands, bug fixes and other changes

- 4.6b20 compatible
- Added new built-in console commands
- COMMANDS displays a list of all available commands
- HELP displays general help information, or details about the given
command
- QUIT quits the application
- Streamlined the example scenes (not done yet)
- Sightly changed color scheme
- Cleaned up the new folder structure a bit
- Fixed most bugs related to the console input losing focus
- Fixed console output mouse wheel scrolling being unrestricted
- Fixed clearing the console not resetting the scrollbar correctly
- Made changes to the public API
- Renamed namespace Wenzil.Console to UnityConsole
- Renamed event Console.onConsoleLog to Console.onLog
- Changed event type of Console.onLog to Action<string>
- Renamed event ConsoleUI.onToggleConsole to ConsoleUI.onToggle
- Renamed event ConsoleUI.onSubmitCommand to ConsoleUI.onSubmitInput
- Moved/renamed event ConsoleUI.onConsoleClear to Console.onClear
- Renamed property ConsoleUI.isConsoleOpen to ConsoleUI.isOpen
- Removed property ConsoleUI.togglableContent as it is no longer needed
- Removed property ConsoleUI.onAlpha as it is no longer needed
- Renamed method ConsoleUI.ToggleConsole() to ConsoleUI.Toggle()
- Renamed method ConsoleUI.SetInputText() to ConsoleUI.SetInput()
- Renamed method ConsoleUI.AddNewOutputLine() to
ConsoleUI.AddNewOutputEntry()
- Changed parameter order for ConsoleCommandsDatabase.RegisterCommand()
- Changed parameter order for ConsoleCommand constructor
- Moved ConsoleCommandDatabase.ExecuteCommand() to
Console.ExecuteCommand()