feat(ui): colorize output; allow to hide exchanges below certain hold…

[benmarten]

• separate CLI output from Portfolio object (#20)
• colorize output
• flip output (+/-) for better understandability
• allow to hide exchanges below certain holdings for exchanges column (#24)

[barryvdh]

Looks better, but wouldn't it make more sense to do the calculations etc in het portfolio part, instead of the Terminal part? So that Terminal is only for formatting. For example when you would want to allow trading, you would want the targets etc.

[benmarten]

Yes agreed ;)