Implement AND and improve formatting and ordering in rvi.rs

src/instructions.rs

@@ -16,6 +16,7 @@ pub(crate) fn find_and_exec(instr: Instruction, core: &mut Core) -> Option<Instr
         0b01100 => match (instr.funct7(), instr.funct3()) {
             // OP
             (0b0000000, 0b000) => Some(rvi::add(core, instr)),
+            (0b0000000, 0b111) => Some(rvi::and(core, instr)),
             _ => None,
         },
         0b00100 => match instr.funct3() {