Add sync status to CLI status

This is also displayed in the watched repository table in the CLI
status. Shows if the repository needs to be pushed or merged.

Not using any fancy UTF-8 symbols for the status as they will not always
work in ruby1.9. Maybe try this later when 1.9 support is dropped.
Small refactoring of the push and merge guards

I think that this makes the logic of the when to push or sync a little
easier to read.