Fixed counting bug in handle_file_sync().

If no files have to be synced (e.g. all changed files are ignored) it
displayed: There are 1 files to sync:

Now it says: There are no files to sync.

Unit test added.
upload local sha1 only if files where pushed
Merge pull request #141 from mkllnk/check-no-files-changed

Check no files changed || counting bug