Add a verbose flag to see where installation hangs

[binarykitchen]

Would be great to have a --verbose flag so that we can see where any installation progress hangs. For example

/var/log ❯❯❯ mas lucky iMovie                                                                                                                                                                                                     
################################################------------ 80.6% Waiting

always gets stuck at 80.6% - I'd like to see what it is trying or waiting for. The exact commands that were executed before and what the command is where it hangs.

That would be awesome. Thanks.

[XVilka]

Met exactly the same problem with another application - TencentMeeting. It stuck at precisely same 80.6%.