Add test for multiple dependencies on base package

This is just a demonstration following on from #51. When there are multiple dependencies on the same lib:

private-libs-duplication --> baz bar
baz --> foo
bar --> foo

`foo` should be moved along to the end.

Current output is:
```
-lprivate -lbaz -lfoo -lbar -lzee
```
expected is:
```
-lprivate -lbaz -lzee -lbar -lfoo
```