Programmatic Command Blocks

Added new textures for these blocks:

• Command Block
• Chain Command Block
• Repeating Command Block
• Test Instance Block
• Test Block (start mode)
• Test Block (log mode)
• Test Block (accept mode)
• Test Block (fail mode)

Some extra features:

• Impulse Command Blocks fade between orange and gold
• Chain Command Blocks fade between turquoise and cyan
• Repeating Command Blocks slowly flash light blue to indicate their function (repeating)