escape filenames correctly

[alunny]

for example, adding a file called Foo+Bar.m to the project

cc @wildabeast

[shortstuffsushi]

I know this is super old, but it seems that this still may be a problem. It seems that there are cases where files aren't properly removed because they're expected (or not expecting?) quotes where they do(n't) exist. I think #19 is related to that as well. Unfortunately, since Cordova's PlugMan relies on this library, I think it also may be breaking their stuff.