This commit adds some internal changes for tracking specific emit options in AST/IR
that can then be passed on to the backend / EMIT.  This will potentially provide a
generic way to extend AST options to the backend.

- add 'enum IR_EMITOPT' for options relating to EMIT options
- add 'AST_OPOPT.AST_OPOPT_DOINVERSE' for relational operators  to indicate that
  the AST expression needs to be inverted.  This allows AST to preserve the user's
  original expression and pass it on to the backend to solve.
- add 'IR_EMITOPT.IR_EMITOPT_REL_DOINVERSE' to indicate the option to the backend
- add 'EMIT_NODE.options' to track options emit options
- Update `EMIT_RELCB` to accept an options parameter
- For procedures handling relational operators in IR/EMIT, add parameters to the
  internal functions to accept 'options as IR_EMITOPT'.  This will then control
  how the backend handles code generation.