made queens.apl a testable example
included examples in the main test procedure
added examples/README
Fix issue #30: remove misleading line of code.
Issue #31: fix primes demo so that it doesn't rely on 0-residue.
Issue #8: implement monadic ○ (pi times) on complex numbers.
Rename "numeric" helper to "real", since it doesn't handle complex numbers.
Add a "numeric" helper to handle real or complex arguments.
Make use of the "numeric" helper for monadic functions.
Make use of the "numeric" helper for dyadic functions.
Simplify the use of the "numeric" helper for dyadic functions.
Issue #8: implement floor and ceiling on complex numbers, following the
Extended APL standard ISO/IEC 13751.
Issue #32: fix residue according to the ISO standard.
identity elements for |!=<≤≥>, issue #16
strand assignment, issue #26
identity operator as ⍁ (U+2341), issue #16
fixed shape for empty array reduction, issue #16
enforced scalar identity elements, issue #16

RANK ERROR is raised if the argument to ⍁ is not a singleton.
A non-scalar singleton is converted to a scalar.
Reformat.
Issue #34: fix mix on items of different shapes.