Add vector instructions.

Use derived type variables with the 'LaneOf' function.

Add u8 immediates to be used for lane indexes and bit shifts.

src/libreader/parser.rs

@@ -669,6 +669,8 @@ impl<'a> Parser<'a> {
                 }
             }
             InstructionFormat::Select |
+            InstructionFormat::InsertLane |
+            InstructionFormat::ExtractLane |
             InstructionFormat::Jump |
             InstructionFormat::Branch |
             InstructionFormat::BranchTable |