Adding support for extra rsync options via rsync.options

I want to use git-fat for special case of deployment of files for the Wikimedia Foundation.  I want to manually manage a git-fat store (no push) using symlinks to .jar files in an Archiva repository. However, currently git-fat does not support rsync's --copy-links, which I need in order to be able to pull down the actual files.

This pull requests allows for arbitrary rsync options settings like:

```
[rsync]
...
options = --copy-links --verbose
```