Cleared Compiler Warnings

Cleared compiler warnings and minor source formatting updates.

Removed servo support

Attaching servos within Brief conflicted with projects wanting to handle this themselves (and then expose higher level words in Brief). If desired, simple servo words may be added per-project very easily.

Added `next` and `nop` instructions.

next is a counted loop, taking a count from the return stack and an operand specifying relative jump back (but positive byte). Jumps back until count < 0. Exits loop without leaving count on the return stack.

Proper useage would be lit 10 x y z next 3. Where 10 is the count, x, y, and z are arbitrary instructions and 3 is the offset relative to next - back to x.

Support in the REPL for a do ... next syntax will be added later.