left- and right-from operators with minimal testing
Basic OP_EQ and OP_NE tests
Simple testing of statement execution/evaluation

No output testing yet.
Refactor TestStatement
Test ‘if’ statement; add inequality evaluation

I’ve made a semantic break with Archetype here, which put all values through eval_compare, even equality checks.
Get strict (and fast) about numeric conversion

The negative sign is handled as the CHS operator, and Archetype doesn’t have floats, so this should be OK.
Test boolean string conversion, incidentally