Reticle designs

Reticle should should have alternative designs and/or colors, opacity, as well as inverted color Java-look. Reticle burn in is a real issue on OLED screens, so a lighter look is essential to prevent burn in during long play sessions.

Additionally it can disappear when it's not needed and provide some feedback: when block is out of reach for pickaxe it can become transparent and even disappear completely when running.