record_end now accepts names with spaces

for example:

```
> record_end "foo bar"
"foo bar_ios6_iphone.base64"
```

fixes https://github.com/calabash/calabash-ios/issues/167 and replaces https://github.com/calabash/calabash-ios/pull/168

@gardner thanks for the pull request!   i believe it should have been made against the 0.9.x branch and not the master branch.