Copy cfignore to upload directory to properly ignore files

[fraenkel]

The source whether directory or zip starts with a .cfignore.
After we create the temp directory for zipping, the cfignore is ignored in the copy. When zipping, the default ignores only apply.

This fix always copies the cfignore if present so we can properly ignore when zipping.

A current workaround is to ignore the cfignore via !.cfignore.

[cfdreddbot]

Hey fraenkel!

Thanks for submitting this pull request! I'm here to inform the recipients of the pull request that you've already signed the CLA.

[goehmen]

https://www.pivotaltracker.com/story/show/76075782

Thanks Michael!

[ghost]

Everything looks good here. Comment was a confusing at first, but it makes sense with a given use case.

some_dir/
    file_1
    file_2
    file_3

in .cfignore
   some_dir/
   !some_dir/file_1

This PR properly uploads just the files with the ! in front of them.