Allow setting of `extract_to` when using `AndFeathers.from_path`

This change allows you to create an archive from a path, and specify the
extract_to field. For my purposes, it allows me to create a archive that
extracts all the contents into the current directory, instead of a directory of
the same name given.

Apologies or lack of test(s), or even running tests, time crunch. If you don't add one yourself, I can
add later. I also lack ruby 2.0.0 atm

Sample usage:
```ruby
file_path = File.expand_path('~/Projects/taas-testing')
archive = AndFeathers.from_path(file_path, '.')
temp_path = '/tmp/a_testing_file.tar.gz'
File.open(temp_path, 'w+') {|f| f << archive.to_io(AndFeathers::GzippedTarball).read}
```

You can extract `a_testing_file.tar.gz` with `tar -xf a_testing_file.tar.gz` and it will extract into the current directory, instead of one named `taws-testing` (or `a_testing_file`, I forget...)