Add tabs to spell lists

[devonjones]

Spell lists are a bear to scroll through. Add tabs at the top by level to make scrolling through it bearable for higher levels.

[HairyDude]

For phones, it'd be better to use collapsible subsections, the way the "Pathfinder Spellbook" app does it.

[devonjones]

Not a bad idea. Thanks!

[NilartPax]

These tabs per level would be great.