Check before unmounting

[vincenzo]

The plugin's default behaviour is to unmount the target before mounting it, just in case it was mounted already.

However, un-mounting when it's not mounted results in an error on the screen (nothing major, but annoying when part of a clean vagrant output)

umount: /Users/vincenzo/Documents/Repositories/solas: not currently mounted

Checking for the mount rather doing umount/mount has also the benefit of less overhead.

I am just not versed at all in Ruby, else I'd make a PR...
I can even manage to identify the piece of code and write what I think it's the fix, but I am really just not sure how to go about testing it then...

[vincenzo]

I decided to take the changes upon myself.
However, I see quietness on this project and I wonder if you are going to be around to merge a pull request, @fabiokr? Else, I'll just fork your project.

[fabiokr]

I'm not using the plugin myself anymore, but I can help with it if you provide a PR.

[vincenzo]

Ok, that's all I need. Thanks @fabiokr.

[istr]

I'm not using the plugin myself anymore, but I can help with it if you provide a PR.

Just out of curiosity: what kind of file system sharing host <-> guest (with good performance) do you use instead now?