Added version information

Version is now displayed whenever ScriptCs is launched.
#132 Version flag as a command

Specifying -version or -v will output version information.
#132 Version flag as a command
Merge remote-tracking branch 'upstream/dev' into dev
#132 adapted to the latest code

Execute now returns a CommandResult
#132 Removing reference to ScriptExecuteCommand.cs

File appears to be removed.  Tried checking this in earlier and it
apparently failed.
Merge pull request #146 from Codatrix/dev

#132:  Added version information