Improve the CLI

[stackotter]

Delta Client has a few command line arguments but there are a few other options that could be very useful such as --logLevel. There is also the NSDocumentRevisionsDebugMode because of Xcode stupidly supplying that option when running the client (and I want strict mode parsing of arguments). This dummy argument could easily be hidden. The usage message also has the name of the cli tool as command_line_arguments, which could easily be changed to DeltaClient.

• [x] Hide the dummy NSDocumentRevisionsDebugMode option
• [x] Create a --logLevel option
• [x] Provide a name for the cli so that it's not just command_line_arguments
• [ ] Add any other arguments that might be useful for debugging or development purposes

[stackotter]

I've cleaned up the cli system a bit and added the --log-level option.

I can't think of any other useful arguments to add at the moment, but they should be pretty easy to add now.

I'll count this as completed