3.0 - Add plugin shell.

It symlinks / copies plugin's assets to app's webroot. Thought this might be handy to use in deployment tasks.

One issue I am having is with plugins with vendor namespace. The task first creates directory for vendor name and then proceeds to create symlink for the plugin's webroot inside it, but it fails resulting in folder being copied instead. 

If the directory for vendor name exists beforehand the symlink is created without problem. So for some reason php doesn't seem to realize the directory exists when it's created by the script itself. Using clearstatcache() doesn't help.
>What about them?

I've used `mod_rewrite` rules on some servers where symlinking was not possible. An advantage could be that you can get "direct" access to the plugin assets without having to create the symlinks or if (grmbl) the hosting-provider doesn't allow shell access, but you *are* allowed to customize the virtualHost.

> there should be a non interactive mode too which copies by default for usage in deployment scripts

OK. Should users be able to have *some* control over which 'strategies' are allowed (i.e. also be able to *fail* if symlinking fails, in stead of always falling back to copy?)

> Run the shell again and the files will be updated. PHP's `copy()` overwrites files.

Yes, but it doesn't *remove* files that are no longer there. Not a major issue in most cases, but could be.


Apart from those; looks like a great feature!