Added support for adding/updating mailbox display name.

[bubbapizza]

Hi, I added a flag to the mailbox command to so I could change the display name of a mailbox. I figured I'd send you a pull request to see if you want it.

Thx Shawn

[corvy]

Thanks for making these pathces @bubbapizza and @rj11 ! Is there a howto compile the tool with these included? I have tried to install golang and run make but I get no binary. Do you have some tips?

[rj11]

Ooof, I can't really remember how I did it. I've only ever used go the one time I made these patches. I think I had to use the go command itself to check out the source code and compile it rather than doing the standard git clone thing.

[corvy]

Thanks, I will have to plonker around with it then.

[eddiewebb]

@corvy - Bubb'as and other recent changes (see #14 ) are in the pre-compiled https://github.com/eddiewebb/iredmail-cli/releases/tag/v0.3.1