Fixed a crash which occurred when overwriting a non-writable property.
Fixed an error in the RegExMatchObject creation code for callouts.
v1.1.16.04
Fixed x.y/[]/{} sometimes falsely being flagged as variadic.
Merge branch 'master' into alpha
Fixed returning ByRef vars.

StealMem from the right var.

`return var` is now always an expression, so aResultToken is set in all
cases by either ExpandExpression or ExpandArgs.  Static/global vars are
returned without copying (except by caller).  Local vars returned via
ByRef are left for ExpandExpression to copy into the deref buffer.
Fixed commands to treat objects as empty strings (not garbage).
Fixed a crash occurring when a for-loop expression causes thread-exit.