Exclude account from current balance when show_on_dashboard=False

[qedi-r]

Resolves Issue #133

• fixes api/balance to only show accounts with show_on_dashboard=True
• creates api/balance to show all accounts regardless of show on dashboard
• adds 'show all accounts' checkbox on charts page

[simhnna]

Sorry for taking this long to respond and thank you for your contribution. I modified the style a little and merged it in #145