0.5.0

• Rename --unbillable option to --include-unbillable for clarity
• That option no longer looks at the Billable flag on a project, only on individual entries (see #4)
• Add erase command for deleting synchronized entries from moneybird (--project can be added to only delete entries for a particular project)
• Add logout command, which forgets Toggl Track and moneybird credentials
• Add login command for symmetry