Add a perDockWidget ContextMenu hook

[pylessard]

Add an overridable hook to extend the context menus.
Would allow someone to extend the CDockWidget class to add some custome feature.

Main goal is to add a "Rename" feature in my project.

[pylessard]

Just a quick note of context. In my application, the user can build a "dashboard". Some CDockWidget can be instatiated at will, some other can only have a single isntance. I want the user to be able to rename his tabs, but not the apps one.

It's a debugger software. The variable list is in a app-wide widget. Use can have many watch/graph windows.

Implementing custom contextmenu with a factory in this case would be a bit clunky. I find this solution more elegant.

Cheers

[pylessard]

I just realized that this may not be very friendly for the state save/reload feature. It would be useful to my application though.

I will leave it to you to decide wether you want the PR in or not. I can probably make it work with a custom factory

[githubuser0xFFFF]

Hi Pierre, thank you very much fpr your pull request, Please consider my review comments.

I like your solution and will merge it after you considered my review comments. If you would like to make your contribution perfekt, you could add a small example to the demo application that shows this features and can be used for testing. Also adding some lines to the documentation that explains this feature would be really nice - but I will also merge it without these additional improvements,