Oops - silly bug here. Should move to source path.
Fixes problem with renaming files across drives.

This was mentioned in issue #8, and is mostly fixed there. However,
it still occurs if part of the /var/cache/aura tree is mounted on
another drive.

This fix follows the normal behaviour unless it encounters an
unsupported operation (thrown when across drives), in which case
it resorts to copying the file instead.
Where there is no package description, show a blank line.

This is the correct behaviour where a package description
isn't supplied, and it fixes (a) cause of issue #104, although
there are others. However, it can also serve to hide
the situation with split packages, which are going to be a bigger
headache in themselves!
Check whether a package is installed before syncing it.

This patch changes the behaviour of -M under the --absdeps option.

This fix partially addresses issue #125 by changing the behaviour
described in issue #122, and only syncing packages which are not
already installed.

This applies only to dependencies of a given package, and not when
a package is specified as the main package. This allows packages to be
reinstalled when required explicitly.
Merge branch 'fixes/issue-125'
Merge pull request #121 from nc6/master

Fix moving files across drives