[TASK] Drop rpAutoMaxHeight directive

Will get replaced by a more generic slider.
[FEATURE] Effects: Add rpSlide directive

Use with div(rp-slide="parameter_to_watch").
[FIX] Balances widget: Fix margins and paddings
[FEATURE] Widgets: Animated show/hide with rpSlide
[FEATURE] Balances widget: Animated currencies show/hide

Uses rpSlide, too.
[FEATURE] Widgets: Animated show/hide caret
[FEATURE] Widgets: Hand cursor for clickable divs

Provides better visual clue that these areas can be clicked to show/hide
parts of the interface.