Shears + FishingRod support to Durability Info, Mouse side buttons for ItemSelector

## Durability info (for #16)
I have added support for FishingRod and Shears for both the durability HUD and for auto-removal. As per suggestion, due to the very low relative durability of FishingRod, it has its own tolerance of 8 durability instead of 15 for auto-removal; please advise if acceptable.

## ItemSelector
As per suggestion, I have added support for mouse side buttons for cycling items on the hotbar. This actually works nicely, in some situations working quicker than using the mousewheel. I have opted for instant switching instead of bringing up the UI when using side buttons. I have also added a config button for toggling this behavior (default: on).

Admittedly, the logic involved in cycling the items is a little messy. There has been a minor change to cycling behavior for both side buttons and mouse wheel usage; it is now a little smarter when going the other way in direction (slots are not "skipped").